Performance Gains: This system produced gains of up to +11 HP and +15 lbs. x Ft. TQ., as measured on our in-house dyno. 3" - 2-1/2" 304 Stainless Steel Construction: This axle-back exhaust system is constructed of 3" - 2-1/2" mandrel-bent 304 stainless steel tubing for maximum strength and durability. High-Flow Stainless Steel Black Muffler: This system features a high-flow stainless steel black muffler, producing a mild sound. The muffler has a black finish for ultimate corrosion resistance. Dual 4" Diameter Black Exhaust Tips: Finishing off this exhaust system are dual 4" diameter black 304 stainless steel clamp-on exhaust tips. The tips features a laser etched aFe POWER logo for a unique style. Installation: Utilizing factory style hangers this system mounts directly to factory mounting locations for a hassle-free installation. Some cutting required. Exhaust Valve: This axle-back exhaust system incorporates a factory style exhaust valve which uses the factory exhaust valve motors (not included). The valve helps regulate, direct and control the flow of exhaust gases by opening, closing, or partially obstructing passageways depending on throttle position for maximum performance. Integrated Mitered Merge Collector: A mitered merge collector is used to decrease turbulence and increase exhaust velocity resulting in increased horsepower, torque and improved throttle response. Computer-Aided Design: Utilizing state-of-the-art computer-aided design technology, this exhaust system is designed for custom, high tolerance factory fitment. MIG-Welded: 100% MIG-Welded for race-proven strength and durability. Emissions Disclaimer: This product does not require a CARB EO#. aFe POWER exhaust systems are engineered and manufactured in our Corona, California facility. MACH Force-XP 3 IN to 2-1/2 IN 304 Stainless Steel Axle-Back Exhaust Black BMW M235i (F22/23) 14-16 L6-3.0L (t) N55 BMW M235i (F22/23) 14-16 L6-3.0L (t) N55 Fitment: 2014 BMW 228i Base 2014 BMW M235i Base 2015 BMW 228i Base 2015 BMW 228i xDrive Base 2015 BMW M235i Base 2015 BMW M235i xDrive Base 2016 BMW 228i Base 2016 BMW 228i xDrive Base 2016 BMW M235i Base 2016 BMW M235i xDrive Base