If there legal in your state,why worry about being quiet, aslong as you have a muffler.
#1 Reason to "be quieter" is that loud pipes give the Law "probable cause" to pull you over. Probable cause
may then cascade to other more serious charges on you. Yes, loud pipes
even with a muffler can (and often are) violation of "nuisance ordinances" and when you eventually confront a Judge or jury , they could frown on you for disturbing their peace