Megan Racing Down-pipes for the newer 2011-12 BMW 3 series 335i/335ix (equipped with N55B30 Single turbo motor) are made of durable 100% T-304 Stainless Steel piping that is polished to a mirror-like finish. This Down-pipe replaces the OEM exhaust piping with all of its restrictive bends while increasing the inner diameter of pipe; this greatly increases exhaust flow and reduces turbulence within the system, as a result freeing up high-end horsepower and mid-range torque. Essentially the missing link to your exhaust system; this down-pipe will give you competitive edge that you have been looking for. Expect an increase in exhaust tone due to freed up exhaust flow. (NOTE: The down-pipe is for off-road use only and is not intended for public highway use.) Specifications & Features: - 100% T-304 Stainless Steel Piping TIG-welded onto computerized CNC-machined flanges for strong, long-lasting durability -4" to two 2.5" collectors - Smooth bends improve flow and performance. - Fits 2011-12 BMW E92 335i Coupe, E90 335i/335ix sedan equipped with single turbo N55B30 motor only.