Dinan engineers designed the F22 BMW M235i exhaust to improve exhaust flow by reducing back pressure, resulting in increased power output and a great sporty sound that is civilized when you want it to be, and pleasantly aggressive under hard acceleration. Dinan also incorporates a Helmholtz chamber design that reduces resonance or ÒdroneÓ at low RPM.ÊThe system is built to exacting specifications to ensure perfect fit using the factory hangers. It is made from 100% 16 gauge 304 stainless steel and will resist corrosion for years to come. The design features twin 89mm ceramic black exhaust tips for a tasteful, high-performance look.