"I put a Borla cat back exhaust on my 2006 Silverado (4.8L, short bed, std cab) last night. I am very pleased. In fact, I am TOTALLY happy with the system! I don't think I have ever had an aftermarket product that fit so well. The fit was perfect. The stainless muffler was nice. The sound is factory quiet at cruise (1000-2000 rpm) and mellow under acceleration. Thanks for a great product."