Vehicle Modifications Engineering

Engineering certification for vehicle modifications — suspension, bull bars, towing setups, chassis and body changes.

Related services

ATM upgrades →

Heavy vehicle engineering (VSB6) →

Vehicle modification engineering →

From the blog

What is a GVM upgrade? →

Understanding VSB6 →

Understanding the vehicle certification process→

Ready to upgrade?

Servicing Northern Territory, Queensland, Western Australia, South Australia registered vehicles Australia wide

Frequently asked questions

How long does the engineering process take?

Timeframes vary depending on the complexity of the project and the documentation required. Straightforward inspections may be completed quickly, while more complex engineering assessments or custom modifications require additional analysis and documentation. Furthermore, difference in wait times are dependent on the regulatory body providing the approval. Each State and Territory has its own body, as does the federal system.

How much does a GVM upgrade cost?

Total cost = engineering certification +shop install. Engineering certification starts anywhere between $1,990 and $5,990 depending on your vehicle type, complexity, and whether there are type approvals available in your state or territory. Shop installs vary from $2,500 to beyond $50,000 depending again on type of vehicle and modifications required/desired. Call us to discuss.

Is your vehicle suitable for a GVM upgrade?

Possibly. It depends on the vehicle model, chassis, suspension, axle limits, brakes, tyres, and intended use. We review those factors to confirm whether a GVM upgrade is suitable and what certification is needed. See our GVM Upgrade Finder tool or call us to discuss.

How do GVM and GCM differ on your vehicle?

GVM is the maximum weight your vehicle can carry when loaded. GCM is the maximum combined weight of the tow vehicle and trailer together. A GVM upgrade may not change GCM. We can help you work out what applies to your setup.

Will a GVM upgrade increase my towing capacity?

Not necessarily. A GVM upgrade increases the maximum allowable weight of the vehicle itself, but it does not automatically increase towing capacity or Gross Combination Mass (GCM). Every vehicle has specific limitations, and these should be considered when planning modifications or towing heavier loads.

What information do I need to get a quote?

To provide accurate advice, we'll generally need:Vehicle make, model and yearVIN (if available)Registration state or territoryDetails of any existing or planned modificationsIntended use (touring, towing, commercial, etc.)Providing this information upfront helps us identify the most suitable engineering pathway and provide an accurate quotation.

What's the difference between pre-registration and post-registration GVM upgrades?

Pre-registration GVM upgrades are done before the vehicle is registered and are often part of a Second Stage of Manufacture (SSM). Post-registration upgrades are performed on already registered vehicles and may have different compliance requirements.

How much can I increase my GVM?

The amount you can increase your GVM depends on your vehicle's make, model, and structural capacity. A licensed engineer can assess your vehicle and determine the maximum allowable GVM.

Can I get a GVM upgrade after my vehicle is registered?

Yes, GVM upgrades can be performed on registered vehicles. However, the process and requirements may vary depending on your state or territory.

Does a GVM upgrade increase my GCM?

No, a GVM upgrade does not automatically increase your GCM (Gross Combination Mass). GCM is determined by the vehicle manufacturer and may require separate certification.

What is a GVM upgrade?

A GVM (Gross Vehicle Mass) upgrade increases the maximum allowable weight your vehicle can carry when fully loaded. This is achieved by modifying components such as suspension, brakes, and axles to meet higher load requirements.

Does a GVM upgrade affect insurance?

Yes, a GVM upgrade can affect your insurance. It's important to inform your insurer about the modification to ensure your policy remains valid.

Is a GVM upgrade legal in Australia?

Yes, GVM upgrades are legal in Australia, provided they comply with the Australian Design Rules (ADRs) and state or territory regulations. Certification by a licensed engineer is typically required.

Can I reverse a GVM upgrade?

Yes, a GVM upgrade can be reversed, but it requires re-certification to ensure the vehicle complies with its original specifications.

Does it affect warranty?

A GVM upgrade may affect your vehicle's warranty, especially if the modifications are not approved by the manufacturer. Check with your dealer or manufacturer for details.

Does it affect resale value?

A GVM upgrade can affect resale value positively or negatively, depending on the buyer's needs. Some buyers may value the increased capacity, while others may prefer an unmodified vehicle.

What modifications are normally required?

Common modifications for a GVM upgrade include upgrading the suspension, brakes, and axles to handle increased loads. Additional components may also be modified depending on the vehicle.

What is vehicle modifications engineering?

Any modification that changes a vehicle’s structure, mass, handling or safety systems — including suspension lifts, bull bars, winches, chassis and body changes, towing setups and electrical systems — may require engineering certification before the vehicle’s registration can be updated.

We assess the specific modification against the applicable technical requirements, verify the installation where required, and prepare engineering documentation for the relevant jurisdictional approval or registration pathway.

Skipping required certification may result in a failed inspection or refused registration. An undeclared or non-compliant modification may affect insurance cover. Confirm notification requirements with your insurer. Read our full guide on what needs certification →

Common modifications we certify

Suspension & chassis modifications

Lift kits, upgraded suspension components, and chassis reinforcement

Bull bars, winches & towing setups

Front/rear protection, recovery equipment and towbar/hitch installations

Body & canopy changes

Tray/canopy fitments, dual-cab conversions and structural body modifications

Our process

Assessment

We review your modification and identify which vehicle standards apply.

Engineering

The modification is assessed for structural and safety compliance.

Inspection

The vehicle is inspected to confirm the modification meets the required standard.

Certification

We issue engineering compliance certification so the modification can be recorded on registration.

Related services

GVM upgrades →

Heavy Vehicle Certification (VSB6)

ATM Upgrades→

GVM Upgrade Finder Tool

From the blog

Modified Vehicle Compliance Inspection: The Essential Engineering Checklist (2026)

Fleet Vehicle Modification Certification: The Complete Engineering Compliance Guide

Overloaded 4WD Legal Risks in Australia: Myths vs. Reality (2026 Guide)

Understanding the vehicle certification process→

Ready to modify?

Servicing vehicles Australia wide

Call now

Our business is to know the rules

So you don't have to.

GVM upgrade possible

Yes - pre registered and already registered vehicles

GCM upgrade possible

Yes pre-registered, and already registered vehicles

Get it certified right, the first time.

Contact KME Vehicle Engineering

A Guide to the Vehicle Modification Process Around Australia...

Northern Territory - more details

Vehicle modification approval in the Northern Territory is administered by the Motor Vehicle Registry (MVR), within the Department of Logistics and Infrastructure. Depending on the vehicle and modification, the pathway may involve MVR assessment or inspection, certification by a recognised engineering signatory and, for significant or extensive light-vehicle modifications, Technical Advisory Committee consideration. VSB 14 is the primary technical reference for light vehicles, while VSB 6 applies to heavy vehicles and may also be used for some light-vehicle assessments.

The NT advises that, in most cases, it will recognise certification from an interstate engineer who is recognised or approved by their home registration authority. Acceptance still depends on the specific vehicle, modification and MVR requirements. Vehicle owners taking an NT-certified vehicle interstate should confirm the receiving jurisdiction’s requirements before relying on the certification.

Heavy-vehicle modifications in the Northern Territory are administered by the MVR. The NT has not adopted the Heavy Vehicle National Law, although VSB 6 is used as the principal technical standard for assessing heavy-vehicle modifications.

Link to NT Vehicle Modification Process

Online Application Call us to start

Queensland - more details

Queensland runs its own scheme rather than deferring entirely to VSB14 — modifications are governed by the QCOP (Queensland Code of Practice: Vehicle Modifications), administered by the Department of Transport and Main Roads (TMR).

Modifications fall into four categories: Minor (accessory fitments needing no approval), Basic, Complex, and Specific. Only complex modifications — engine upgrades, suspension upgrades, mass re-rating, gearbox changes, vehicle body modifications, steering and brake replacements — require certification, and that certification must come from an Approved Person, accredited under TMR's Approved Person Scheme based on their industry experience and qualifications.

An important state-specific quirk: modifications performed and certified in another jurisdiction are not automatically recognised in Queensland. If a vehicle was modified and certified interstate, it generally needs to be re-approved by TMR or re-certified by a Queensland-approved person before Queensland registration — this matters for any customer bringing an interstate-modified 4WD into QLD.

Link to QLD Vehicle Modification Process

Application Form Call us to start

Western Australia - more details

Western Australia uses a tiered Minor, Simple and Complex modification system administered by the Department of Transport and Major Infrastructure (DTMI). VSB 14 may provide relevant technical guidance, but WA also applies its own Vehicle Technical Bulletins, Information Bulletins and approval requirements.

Modifications fall into four categories: Minor, Basic, Complex and Specific. Complex modifications — including many engine, suspension, mass-rating, body, steering and brake changes — must follow an applicable Queensland-approved modification code and be certified by an Approved Person authorised for that code. Specific modifications are those for which no Queensland-approved code exists; they cannot be certified by an Approved Person and require direct TMR approval in limited circumstances.

A vehicle that remains registered in another Australian jurisdiction can generally travel in WA under the ratings and approval recorded in its home jurisdiction. However, transferring the vehicle to WA registration is different: the modification must satisfy WA requirements and be accepted by DTMI. Owners should confirm this before purchasing or transferring an interstate-modified vehicle.

Link to WA Vehicle Modification Process

Online Application

South Australia - more details

South Australian light-vehicle modifications are administered by the Department for Infrastructure and Transport (DIT). Significant modifications may require an application before work begins, a Statement of Requirements, assessment by a recognised Light Vehicle Engineering Signatory and final acceptance by DIT.

Pre-registration and in-service mass changes follow different approval pathways. Whether a GVM or GCM re-rating is available depends on the specific vehicle, proposed rating, technical evidence and DIT requirements. A GVM or GCM change does not automatically increase the vehicle manufacturer’s braked towing capacity.

Tyre, suspension and body-height changes must be considered together, including their effect on overall vehicle height, handling and applicable testing requirements. Owners should confirm the required approval and testing pathway before commencing the modification.

Link to SA Vehicle Modification Process

Online Application Call us to start

New South Wales - more details

NSW runs off VSB14 like most other states, but is also administered through its own certification scheme — the Vehicle Safety Compliance Certification Scheme (VSCCS), run by Transport for NSW. VSCCS licenses individuals (not businesses) to inspect non-standard and modified vehicles and issue compliance certificates electronically; certifiers need a minimum Certificate IV in a relevant discipline, and must carry significant public liability and professional indemnity insurance. A second tier, VSCCS J&P, covers heavy vehicle body-fit and tow coupling/fifth-wheel modifications specifically.

NSW has also published its own supplementary guidance beyond the national code — a dedicated light vehicle modifications manual covering suspension and ride height — meaning NSW customers may need to satisfy state-specific detail on top of the base VSB14 requirements, not just the national standard alone.

NSW requirements for tyre, suspension and body-height changes depend on the vehicle, the combination of modifications and the applicable NSW Suspension and Ride Height Manual. Significant modifications must be assessed and certified through the VSCCS pathway; owners should not rely on one general height limit without checking the vehicle-specific requirements.

GVM and GCM re-ratings are also vehicle- and evidence-specific. A licensed VSCCS certifier should be consulted before work begins to confirm the applicable standards, inspections and registration-update requirements. GVM, GCM and braked towing capacity are separate ratings, and changing one does not automatically increase the others.

Link to NSW Vehicle Modification Process

Call us to start

ACT - more details

The ACT doesn't run its own named certification scheme like VASS or VSCCS — instead it applies the National Code of Practice (NCOP) and VSB14 directly, with significant or extensive light vehicle modifications requiring certification by a recognised engineering signatory before the vehicle can be re-registered.

Because the ACT largely defers to the national standard without heavy state-specific amendment, it's generally treated as one of the more straightforward jurisdictions to work with. However, confirm the applicable pathway with KME or Access Canberra rather than assuming the ACT requirements mirror those of NSW or Victoria.

Read our complete guide here→

Link to ACT Vehicle Modification Process

Call us to start

Victoria - more details

Victoria administers modifications through the Vehicle Assessment Signatory Scheme (VASS), run by Transport Victoria (formerly VicRoads). VASS-approved engineering signatories assess and certify modifications against VSB14. A VASS approval certificate for a light vehicle is only valid for 30 days from issue — the vehicle must be presented for roadworthy inspection and registered within that window, or the certificate lapses. Certificates for modified heavy vehicles don't carry this expiry. Also worth noting: only Victorian residents/entities are eligible to be authorised as a VASS signatory in the state — an interstate engineer can't hold a VASS authorisation.

Victorian requirements for tyre, suspension and body-height changes depend on the vehicle and the applicable VicRoads guidance or VASS approval pathway. GVM and GCM re-ratings are vehicle- and evidence-specific, so eligibility should be confirmed with an appropriately authorised VASS signatory before work begins. A change to one vehicle rating does not automatically increase the others.

Worth flagging for VIC customers: the 30-day validity window on light vehicle VASS certificates means timing between certification and registration matters more here than in most other states — a delay in booking the roadworthy/rego appointment can mean redoing the certification.

Link to Victoria Vehicle Modification Process

Call us to start

Tasmania- more details

Tasmania administers vehicle modification certification through the Approved Vehicle Certifier Approved Inspection Station (AVCAIS) scheme. The certifying authority is the Registrar of Motor Vehicles through Transport Services, which is now a division of Building Tasmania.

An Approved Vehicle Certifier assesses the modification against the applicable vehicle standards, including VSB 14 and Tasmania’s Vehicle Modification Certification Manual. Where the requirements are satisfied, the process may include a modification certificate and modification plate.

Tyre, suspension, body-height, GVM and GCM requirements depend on the specific vehicle and modification. Owners should confirm the applicable certification, inspection and registration pathway with an Approved Vehicle Certifier before commencing significant work.

Link to Tasmania Vehicle Modification Process

Call us to start

Independent engineering you can trust

KME provides independent engineering advice and certification. We recommend solutions that are evidence based, practical and suited to what your vehicle is needed for.

Fully compliant

ADR and state regulations
Engineering certification
National experience

Vehicle-Specific Advice

Touring vehicles
Work utes
Fleet vehicles
Heavy vehicles

Australia wide

Remote assessments
Dealer support
Interstate certification
Jurisdiction-specific pathways

Experienced

15+ years of engineering
Practical advice
Fast turnaround
Real technical knowledge

Frequently asked questions

Northern Territory Application for Approval Process

The types of vehicle modifications allowed and process of certification from the Motor Vehicle Registry office in the Northern Territory is detailed in the links below.However, we are here to help you decipher and understand the process. Give us a call and we will walk you through what YOU need.

South Australia Vehicle Modification Process

The SA Department of Infrastructure and Transport has an online application for modified vehicles - you can follow the links below to both the application and the process.

Western Australia Vehicle Modification Process

The WA Department of Transport has an online application for modified vehicles - you can follow the links below to both the application and the process.

What happens after my vehicle is approved?

Once the engineering assessment is complete and the vehicle meets the required standards, we provide the relevant report or certification. You can then use it for registration or compliance purposes, depending on the approval type and jurisdiction.

Can I install a rear bar?

Yes, rear bars can be installed, but they must comply with safety and design standards. Engineering certification may be required depending on the design and impact on the vehicle.

Can I fit a canopy?

Yes, canopies can be fitted, but they must comply with safety and design standards. Engineering certification is generally not required unless the canopy affects the vehicle's structure.

Can I fit aftermarket seats?

Yes, aftermarket seats can be fitted, but they usually require engineering certification to ensure they meet safety and compliance standards.

Which modifications don't require engineering?

Minor modifications that do not affect the vehicle's safety or compliance with ADRs usually don't require engineering. Examples include fitting accessories like roof racks or tow bars, provided they meet manufacturer specifications.

Can I convert a vehicle to a motorhome?

Yes.Converting a vehicle into a motorhome often involves structural, seating, electrical, gas and weight-related modifications.Engineering certification may be required depending on the work undertaken.We can assist throughout the design, assessment and certification process to help ensure the completed vehicle complies with the relevant standards.

Can I modify a tray?

Yes, trays can be modified, but significant changes may require engineering certification to ensure safety and compliance.

Can I install a body lift?

Yes, body lifts can be installed, but they often require engineering certification to ensure compliance with safety and design standards.

Can I fit larger tyres?

Yes, larger tyres can be fitted, but they must comply with state or territory regulations. Significant changes may require engineering certification.

Can I fit long-range fuel tanks?

Yes.Long-range fuel tanks are a popular modification for touring and commercial vehicles.Provided the tank is suitable for the vehicle and installed correctly, engineering approval is not always required. However, modifications involving structural changes or alterations to the fuel system may require engineering assessment.

Can I modify seating?

Yes, seating modifications are possible, but they typically require engineering certification to ensure safety and compliance with ADRs.

Can I modify chassis rails?

Yes, chassis rail modifications are possible, but they require engineering certification to ensure structural integrity and compliance with ADRs.

Can I modify brakes?

Yes, brake modifications are possible, but they often require engineering certification to ensure they meet safety and compliance standards.

Can I install a winch?

Yes, winches can be installed, but they must be mounted securely and may require engineering certification depending on the vehicle and mounting method.

Can I modify suspension?

Yes, you can modify suspension, but it may require engineering certification depending on the extent of the changes and their impact on the vehicle's safety and compliance.

Which vehicle modifications require engineering?

Modifications that affect the vehicle's safety, structural integrity, or compliance with Australian Design Rules (ADRs) typically require engineering. Common examples include:Suspension modifications beyond prescribed limitsGVM upgradesBrake upgradesChassis modificationsSeat and seatbelt modificationsEngine conversionsSteering modificationsWheelbase alterationsBody changesCertain tyre and wheel combinationsWe can assess your proposed modification and advise whether engineering certification is required.

Daly was a pleasure to work with and has a wealth of knowledge, which he is happy to share. He is able to explain ADR requirements in simple terms and is more than happy to help customers understand the pathway to certification.

Steve P.

Very professional and efficient service. Daly is very knowledgeable and obliging and a pleasure to deal with.

Duncan T.

I can't complain about getting my GVM upgrade the same day I asked and paid!! Too good to be true. Amazing service.

Jamie L.