The new Flowmaster® Flow FX® cat-back exhaust system for the 2011-2019 GM Silverado/Sierra 2500/3500 HD trucks with the 6.0-liter engine is manufactured using durable 409 stainless steel throughout and features 3.50-inch mandrel bent pipes for better exhaust gas flow, and a Flow FX "straight-through" muffler is used for a moderate sound l...