MagnaFlow Diesel Pipes are available for Cummins, Powerstroke and Duramax applications. Each downpipe, extension pipe, muffler delete and tailpipe is made of 100% stainless steel to ensure durability and mandrel-bent to ensure maximum performance gains. MagnaFlow Diesel pipes deliver reduced exhaust temperatures, a boost in horsepower, torque and throttle response. Turbo Outlet Down Pipe; 4 in.; Single; Mandrel-Bend; Upgraded front pipes for optimized performance.