The Dinan Resonator Delete Kit for the F90 M5 introduces a more aggressive tone and an increase in volume over the stock system. Coupled with the associated Dinan exhaust, the sound is further enhanced into a smoother, fuller and more aggressive note that is to be expected of a stately performance sedan. This piece removes the hydro-formed factory resonated section and replaces it with 80mm T304 stainless steel tubing for freer flowing capabilities. In place of the factory resonator itself, Dinan incorporates a beautifully crafted X-pipe made from mandrel-bent tubing for minimum restriction, unlike stamped X-pipes, which are commonplace in the market. This sophisticated 'X' is not only the focal point of the system in terms of aesthetics but also the star when it comes to the effects on the sound. Promoting even flow to both banks of tips, the 'X' removes unwanted nuances in sound caused by uneven exhaust flow that is often in stock systems. Stainless Steel - 3.25" - F90