100% TIG-Welded by certified craftsmen for race proven strength and durability. TIG-Welding provides the strongest welds reducing stress cracks. Paired opposite firing cylinders with equal, specifically tuned primary lengths maximizes scavenging and increases torque throughout the powerband. High grade stainless tubing with a uniform brushed finish provides a beautiful look and high resistance to corrosion. aFe has designed this system to retain all your factory sensors for a hassle free installation. Also included are extensions for a simple plug & play installation. High quality laser cut header flanges provides superior sealing at the head surface. Machined flanges and USA made stainless v-band clamps provide a simple to install leak free joint between the headers and X-pipe. A direct bolt-on system which requires no cutting or drilling to provide a hassle-free installation. This system is constructed of mandrel bent, stainless steel brushed tubing for maximum performance, corrosion r esistance and strength eliminating cracking. This system includes dual, hi-flow, 200 CPSI, stainless steel catalytic converters for maximum flow and performance. aFe PFADT Series Headers & X-Pipes are engineered and manufactured in our Corona, California manufacturing facility. This system is not currently CARB exempt and is not available for sale in California or for use on any vehicle registered with the California Department of Motor Vehicle. Twisted Steel 4 IN 409 Stainless Steel Race Series Down Pipe BMW 328i/428i (F30/F32) 12-16 I4-2.0L (t) N20 BMW 328i/428i (F30/F32) 12-16 I4-2.0L (t) N20