if you already have dual exhaust ( which you probalby dont since you said its not a P71, and the only civie ones to get duals were the HPP cars) you wont see anymore power. but going from single to dual exhaust is only worth about 10hp.
Your car wont be very loud since you still have 4 cats on it. you dont have to worry about getting oulled over, my 85 vic has longtubes and Flowmaster 50's, and dumps. loud as hell and cops dont even look, even when i had the 40s on it they never cared.
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