I've been noticing with no small distress the extremely large numbers of performance cars with aftermarket rims, FMICs etc driving around in Perth at the moment with 'yellow stickers' - the defect notice stickers that police apply to a windscreen when they determine that a car isn't roadworthy, forcing it to be taken to a licensing centre for inspection and clearance. There is clearly an agenda within the WA police force to target such vehicles, which is inconvenient at best and financially crippling at worst for WA car enthusiasts (imagine having to get a car cleared with substantial modifications done to it - in some cases it could costs tens of thousands of dollars). I was intending to post this in the WA section of the forums, but then thought a discussion of engineering certification in general could benefit anyone in Aus. If admins feel differently, feel free to move the thread. What I'd like to find out is if anyone knows what the regulations are in each state regarding aftermarket parts and modifications, so we can work out what we need to do to make our cars compliant and immune from Police harassment. Such shared knowledge could also lead to finding someone with the requesite qualifications that's sympathetic to our predicament, who would be willing to provide the relevant documentation or service at a fair rate. So what do we all know?