The aFe ATLAS turbo down - pipe is engineered to outflow and outperform the restrictive, OE down - pipe on your 2004.5 - 2010 Chevy Silverado or GMC Sierra 2500HD3500HD with the Duramax V8 6.6L turbo diesel. The 3 mandrel bent steel tubing offers smoother transition bends for increased airflow, delivering quicker turbo spool times. CNC machined V - band inlets and outlets ensure an OE - style, 360 degree sealing surface. Coated with a black finish, the ATLAS turbo down - pipe is wrapped with thermal header tape to reduce EGT's even in the most extreme environments. Flow and Performance The ATLAS turbo down - pipe is made from 3 mandrel bent steel tubing offering smoother transition bends for low turbulence to deliver quicker turbo spool times. Perfect Fit The ATLAS turbo down - pipe is an upgrade to the OE down - pipe and utilizes the factory mounting locations for true bolt - on performance. Leak - Free Seal High quality OE style CNC machined V - band flanges are used for a complete 360 degree sealing surface. Finish This down pipe is coated with a black finish and wrapped in thermal header tape for better insulation. This reduces EGT's and under hood temperatures. Note This system is not currently CARB exempt or available for sale in California, and cannot be used on any vehicle registered with the California Department of Motor Vehicle. This item in not legal in NY for use on vehicles with CA emissions.