Hey Ppl!
Fyi Information from Vehicle standards at Regency park is that vehicles that meet ADR 83/00 2005 onwards, any modifications to the exhaust must meet ADR83/00. So the noise level requirement of 90db doesnt apply. Its looks fairly involved as to what the requirements are....
The Australian Design Rules
or
http://www.comlaw.gov.au/ComLaw/Legislation/LegislativeInstrument1.nsf/0/926683FEBEE79567CA2570BA0001641A/$file/ADR+83.00+FRLI+Oct+05.doc
Noise level testing is very ambiguous though, you can get different results from different people using the same equipment. The testing requirements are different to what a copper might do on the side of the road too. If he makes you give the accelerator a punch and it's really loud, this is you causing the noise not the the car being over the limit. Because people are involved, emotions and attitude tend to get involved so even though your car may be under the limit, you will probably get stickered every time if you are a smart arse.
Unless your are a wanker or your car sounds like a helicopter, 99% of people will never be hassled regarding exhaust noise when it is within reason.
"Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind."
- Theodor Seuss Geisel
The policeman that pulled me over to check and then defect me for ride height and wheels, also checked my exhaust. He said it was ok after I gave it a few revs though, but he's probably one of those guys that checks the exhaust with every car he pulls over.