Not sure which 2004 GMC Sierra Performance Mufflers are right for you? We have over 976 customer reviews, with an average rating of 4.5, to help you find exactly what you're looking for. Here's what some of our customers have said:
"very easy to install, only thing is they dont expand the inlet which the pipe from catalytic converters would tie into. ( inlet of muffler) other than that sounds niiice! not too loud but has a real nice growl" —Mike C from Wakefield, MA bought a Magnaflow Performance Mufflers for a 2004 GMC Sierra.