Before you modify - checklist

Confirm your vehicle's state of registration — that state's rules apply, not where you live or drive.

Check whether your vehicle is heavy or light. Over 4.5 tonnes GVM means heavy vehicle standards (VSB6) apply instead of the light vehicle code (VSB14).

Identify the modification category. Most states classify mods as Minor, Basic/Simple or Complex — only complex changes generally require certification.

For Western Australia: get approval in principle before starting any complex modification, not after.

Use an engineer or examiner authorised in your specific state (VASS, VSCCS, RES, AVCAIS etc.) — out-of-state sign-off may not be accepted.

Don't assume an interstate-certified modification transfers automatically — confirm with the destination state first.

Get Quotes and a realistic timeframe. Don't plan this in the last minute before you head off on a trip! Factor in inspection, testing (brakes, ESC, towing where relevant) and paperwork processing time, not just the physical work.

Carry out the modification to spec

Have the work done exactly to the engineering approval — deviating voids the certification.

Keep all certification paperwork and mod plates — you'll need them at registration, roadworthy, and any insurance claim.