I converted my single exhaust on my 3.1 SE to duals using GMPP's cat back exhaust system which is actually a magnaflow cat back system for the 3.8 GT's and comes with polished SS maganflow mufflers for the GT, SS tips, and a polished SS magnaflow resonator as well as a 2.5 inch y pipe made from 409 stainless steel. Very satisfied with the end result-power increase, sound, mileage, and engine temperature reduction-all good! Well worth the $450 I paid for the whole kit-gmpartsdirect.