nah, let off the gas, hit the clutch and cruise till you pass the cop, the rpms will be dropping so you wont even hear the sound of your car youll just hear wind, at idle their not louder then flowmasters, once you get past 2krpm they SCREAM, once you get past 4krpm, its like nascar.
heres a good incar clip, 40mph 2nd gear roll, the video was made for another purpose but itll do, you get the idea of normal driving, high rpms and letting off the gas. Turn up your volume ALOT, speakers on my camera arent good.
http://media.putfile.com/40rollgear
not sure how strict cops are over there, ive heard of people at school getting tickets for their civic being too loud but Ive NEVER been pulled over for my exhaust, I pass cops at high rpms not problem, as long as im not speed or dont take off at the light spinning i usually go pretty fast to piss them off without breaking the law, never had anything said to me about my exhaust though, i dont even worry about it, then again, i am in florida so no emissions = no cats, but still could get pulled over if its too loud.