1998 US Treaty with the UN. Global Harmonization of Motorized Vehicles based on European Standards. California's SB435. Massachusetts trying to get a bill passed to make it illegal to sell loud pipes. Ken Feith of the EPA Air and Radiation department going after motocycle exhaust manufacturers; threatening them with a $10,000 fine per pipe. Yes loud pipes DO save loud. How loud is too loud? That is the argument. The volume is directly related to the throttle. Me I like em louder than stock but not ear splitting. Yes, some bark their pipes just to make noise. To me that is like shooting your gun up in the air just to hear it. Barking the pipes just to make noise is as silly as laying on the horn all of the time.
If you like loud pipes...better wake up and see what is going on in your backyard. By the way hand held decibel meters are against Federal Guidelines. Even though states like Maine have passed laws allowing this, Fed trumps state, state trumps county and so on.