Fits 2011-2014 Mustang GT. Fits 2012-2013 Mustang BOSS 304 stainless steel muffler body construction with 304 stainless steel chrome plated "Ford Racing" embossed 4" exhaust tips Louder, throatier exhaust note Designed to eliminate exhaust drone at sustained RPMs Requires factory muffler clamps 49 state drive-by noise legal (not legal in CA)