I have mixed feelings about this law or proposed law. On the one hand, I drive a car that, from the factory, without modification, has an attention getting exhaust. On the other hand, I certainly consider myself to be among the enthusiast crowd of people who like to wring every last bit of performance or otherwise enjoy all hat my cars have to offer.
Unfortunately, what you're seeing in Massachusetts (and I live in Philadelphia, PA) is a reactionary posture from a people who have seen the pendulum swing too far in one direction, so to speak. I can't tell you how many times the walls of my apartment have been shaken by what I affectionately call "boom cars." There's no reason for this other than driver/owner vanity. As a retired Chevrolet engineer, I can tell you that exhaust notes are tuned for customer satisfaction purposes and not raw horsepower. We all know that if you listen to a Lexus engine (and those of many premium brands, that these engines are nearly silent and yet many of these cars are rockets with surprising high highway top speeds.) So, if you don't want to be regulated, don't be so obnoxious about sending your exhaust sounds to my ears where they represent unwanted cacophony. Thanks.