The primary catalysts on the E9X M3 are the single most restrictive part of the factory set up. Removing these allows the engine to breathe more efficiently and provides more power and torque throughout the rev range.

Our customers demanded a solution that would fit the stock rear section (or any aftermarket exhaust that fits the stock X pipe) and that did not increase the volume too much. 

We therefore developed an X Pipe which would fit the standard rear section and produce a sophisticated noise with high quality secondary catalytic converters and resonators to temper the volume. The car will still pass UK MOT emissions testing with this fitted. 

Power gains alone from this section are in the region of 25-30hp and 25lb/ft torque.