Nice, i'd love to hear this thing on gate, it would be epic i'm sure.
Your in NSW, the worst state for EPA. Dont you guys have portable EPA detectors that sit on the side of the road, analyse the exhaust gas of your car, take a photo if its not correct and send you a nasty fine. Kind of like a speed camera? I've heard this before from several people.
Anyway, its quite a big no no, massive fines for it, attracts stacks of attention.
However, i'm one that is all for a screamer