This full mid-section kit removes the hydro-formed factory center section, including the resonator, and replaces it with larger 3.25" T304 stainless steel tubing for freer flowing capabilities. In place of the factory resonator, 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 hand-made '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 found in stock systems. Along with the inherent benefit of increased volume by removal of the resonator, the Dinan X-Pipe for the F9x X5M/X6M produces a louder, smoother and fuller exhaust note.