The F8x M3/M4's are an audible treat right off the showroom. Coupled with a Dinan exhaust however they become a symphony of aural delight that even the most discerning ear will find pleasing. Dinan's Free Flow axle-back exhaust system features 100% stainless steel construction measured to exact specifications to ensure proper fit via factory hangers and mounting points. Dyno tuned for maximum exhaust flow with minimum backpressure, this system is designed to provide a more aggressive sound under acceleration, while reducing drone inside the vehicle, thanks to computer-controlled valves that limit noise during low-speed driving and open fully during high-load conditions to allow free flow. The exhaust gasses exit through larger laser engraved polished, or ceramic black, quad tips. Every Dinan product comes with our industry-exclusive factory matching new car bumper to bumper warranty and is designed and tested in Morgan Hill, California and can be purchased and installed at any Dinan Approved BMW dealership nationwide.