Bmw Z4 2011 2.5 S Drive 23i Fullset Dual Valvetronic Exhaust System Performance Exhaust Headers Private Label Mfg J's Racing 4 2 1 1st Gen Header B18C Craigersheaders SPD Performance Products Performance SUV Subaru BRZ (ZD8) Exhaust System iPE Official. Introducing the SPDZ1 B Series Ultimate Performance header, engineered for enthusiasts who demand the best in exhaust technology. This advanced 4 2 1 header design provides enhanced power delivery across the entire RPM spectrum. With its race inspired construction, this header is essential for anyone looking to elevate their vehicle's performance. Constructed from high quality 304 stainless steel for durability and longevity. Backed by a one year limited warranty for peace of mind. Features a true 2. 5" collector for superior exhaust flow. CNC machined manifold flanges ensure precise fitment. Flange thickness of . 38" for added strength. This exhaust header is ideal for 1. 6L 2. 0L engine displacements, enhancing horsepower and optimizing exhaust flow for maximum efficiency. Experience improved acceleration and responsiveness with this cutting edge solution. Details: EF & DA models will require aftermarket subframe or traction bar setups for installation. Material thickness of 18G on the 304 stainless steel, measuring . 049" to . 050" for optimal performance. One piece design minimizes potential leaks and enhances structural integrity. Some applications may require minor adjustments to the sump for perfect fitment.