aFe's 4-inch Atlas exhaust is available for diesel trucks. It's made of mandrel-bent aluminized steel tubing, helping improve flow, increase horsepower and torque, and lower exhaust temperature. A two-piece tailpipe and bayonet-style hangers make installation easier. The system comes with a 12-inch free-flowing straight-through muffler. These Atlas systems are either turbo back or down-pipe back, with or without the muffler, and start at $309.