The Mach Force XP cat-back exhaust system produces 11 hp and 10 lbs./ft. of torque. constructed from 2.75 in. mandrel bent 304 hand brushed stainless steel and utilizes a unique crossover pipe that helps to equalize exhaust pressure and tunes the exhaust pulse. Comes with dual 3.5 in. polished 304 stainless steel tips and muffler to build a mellow yet powerful sound. Engineered and manufactured in our Corona Ca manufacturing facility. All systems use factory mounting locations providing stability a nd hassle-free installation. High quality band clamps are used for a complete 360 deg. sealing surface. A free flowing muffler is used to absorb high pitch tones producing a powerful sound and unleashing all available horsepower and torque. The crossover balance tube equalizes and evenly distributes exhaust pulses traveling through the exhaust system. This not only creates more efficient flow and better performance it also reduces sound decibels ultimately minimizing exhaust drone. MACH Force-Xp 3 IN 304 Stainless Steel Axle-Back Exhaust System w/Black Tip BMW 135i (E82/88) 08-13 L6-3.0L (t) N54/N55 Fitment: BMW 135i Base 2008 to 2013