The Dinan X-Pipe Kit for the F97 X3M and F98 X4M 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 befitting of the performance SAV. Replaces the hydro-formed factory resonator between the catalyst and rear muffler with a 70mm T304 stainless steel X-pipe for freer flowing capabilities and a louder, smoother, fuller sound. Made from 2.75" (80mm) 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 present with stock systems. Manufactured 100% from 304 stainless steel with a brushed finish for long life. 304 Stainless is also lighter than stock 10 lbs vs 8 lbs. Easy bolt with included mounting hardware and instructions.