Quote Originally Posted by tinkerbell View Post
it changes NOISE and EMISSIONS and is therefore illegal because it changes the car from the way it was complianced to something that is now uncomplicanced under the Australian Design Rules.

http://www.dotars.gov.au/roads/envir...act/index.aspx

and ADR's are here:

http://www.dotars.gov.au/roads/motor...dr_online.aspx

check out ADR28 and ADR79
Compliancing for intake and exhaust means they must meet ADR/EPA limits. Not sure about exhaust gas emissions, but for intake and exhaust noise, the limits are for cars under 150kW and 2 tonnes is 77dB when moving and 90dB when stationary as stated in ADR 28 that you posted.