The unfortunate facts are that alot of our cars are loud, BUT!!!!! Generally only when you have the go fast pedal down on the floor, not when driving normally. The police force will not care if your car is moderately loud, if your car "LOOKS" loud, then you will get slapped with something, and it may be in the mail. I have had this done in the past, Evo front bar, Shinny cooler, non factory wheels = Must be to loud, and this was measured in a 50zone, front on, doing 20km in traffic, from a distance of no less than 50m.
So be warned, if it "LOOKS" loud, epa, canary etc etc etc will follow.