Each BBK Full length header system is CAD designed and manufactured with 1 5/8"" CNC mandrel bent tubing for unrestrictive airflow and a one piece 3/8” laser cut flange for added strength and durability.ALL BBK exhaust headers are pressure tested to ensure leak free performance. Each BBK full length exhaust header system has been designed and dyno tested at the BBK headquarters in Southern California for Maximimum performance. Results have shown an additional 14-22 rear wheel horsepower over stock. BBK's Mustang full length headers are recommended for built engines and high performance applications. They offer BBK's distinctive quality that guarantees many years of top performance. These BBK CNC Series full length headers for the 2005-2008 Mustang GT are available with optional high-temp Silver polished ceramic coating or a chrome finish. All exhaust header kits include new gaskets and hardware. Please note: *BBK full length headers require a BBK short X pipe or H pipe to complete installation to the cat-back exhaust system- see recommended additional parts *These BBK Full Length Headers are Specifically Designed to Fit ALL 5 Speed & Automatic transmissions.