Free up your BMW's N55 engine with the COBB 3" Downpipe! This direct replacement for the factory downpipe features a 200 cell count high flow catalytic converter and 304 stainless steel tubing. The CNC machined v-band flange and the cast merge section ensures perfect OEM-like fitment. All of these features combine to provide a free flowing exhaust outlet for high energy exhaust gases to reduce turbo back pressure and increase turbo efficiency. Off-the-shelf mapping available for Accessport part number AP-BMW-002 so it's perfectly tuned out of the box.