aFe Power’s new Twisted Steel header delivers more horsepower and torque while outflowing the factory exhaust manifold. The header is constructed of 14-gauge 409 SS tubing with a 1/2” thick head flange to ensure a leak free seal. To eliminate dead space that can cause turbulence and hindering flow that formed collectors are prone to produce, a true merged collector and optimized tube lengths are used for true pulse control technology improving flow and performance. 100% hand TIG-welded construction ensures optimal strength and durability. The smooth curves and increased diameter of this header helps remove restriction and keeps exhaust gas flowing smoothly for improved performance and durability on and off the trails. All components are supplied for a hassle-free installation with no modifications necessary. PartNumber : afe48-36314-HC Description : Twisted Steel Header; 1 5/8 in. Primary Tubing; Merges Into 2.5 in. 3 to 1 Merge Collector; Incl. Dual High Flow SS Catalytic Converters; Retains Factory Sensors; Tube Direction : Down Swept Coating/Finish : Stainless Steel Collector Tube Size (in.) : 2.5 Engine Make/Size : BMW 3.2L Application : Automotive Material : 304 Stainless Steel Tube Size : 1.625 Port Shape : Same As Port/Can Be Matched 2001-2006 BMW M3 Base L6.3246cc Exhaust, Mufflers & Tips::Headers & Manifolds