Dinan Free Flow Axle-Back Exhaust - 2011-2016 BMW 550i

Dinan's Free Flow Axle-Back Exhaust improves 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 harder acceleration with zero drone. 100% stainless steel construction and exacting specifications ensure that the system fits correctly using the factory hangers and will resist corrosion for years to come. A vacuum controlled butterfly valve is utilized to improve flow at wide-open throttle while keeping things civilized and "drone" free throughout. The design reduces overall weight as well and features 3.5'' polished, or ceramic black, tips for a tasteful high-performance look.