This Flowmaster® Flow FX® cat-back exhaust system for the 1999-2006 GM 1500 trucks (2007 1500 Classic) with the 4.3, 4.8, or 5.3-liter engine (Crew Cab 5.5' bed, Extra Cab 6.5' bed only) is manufactured using durable 409 stainless steel throughout and features 3.00 to dual 2.50-inch mandrel bent pipes for better exhaust gas flow. A Flow FX "straight-through" muffler is used for a moderate to mild sound level and maximum performance. Maximum increases on the dyno revealed +14 hp and +13 lb-ft at the rear wheels. This system exits out the same side, in front of the rear wheel on the passenger with dual 4.00-inch black ceramic tips for added style and a custom look. The system uses all the existing factory hanger locations and includes installation instructions and all necessary hardware for an easy installation that you can do at home. Backed by Flowmaster's Lifetime Limited Warranty.