Motorcylces have different noise restrictions that cars. And if you want loud/legal/good sounding your best bet will prolly be SLP Loudmouths, that's what a lot of the newer Stangs are running for something that sounds good and is loud

 

dude if it ain't legal, then say it is, that's what we do down here in alabama, and if you want REALLY loud run some simple plain old strait pipes hehehehehehe now we're cookin with hot grease boys