The aFe MACH Force-XP cat-back exhaust for 2014–2016 BMW M235i (F22/23) uses 3" to 2.5" mandrel-bent 304 stainless tubing, a high-flow muffler and dual 4" black 304 stainless tips. It's a direct bolt-on system using factory-style flanges and hangers and includes a factory-style valve (factory motor not included). Measured gains up to +18 HP and +27 lb-ft on aFe's in-house dyno are reported.
aFe MACH ForceXP 3IN to 2.5IN 304SS Cat-Back Exhaust System w/ Black Tips 14-16 BMW M235i (F22/23)