• Gain up to 23whp/29wtq 

• Faster Turbo Spool 

• Improved Exhaust Sound

• Upgrade to Stage 2+ Tuning

• SS304 Stainless Steel

The ARM N55 Catted Downpipe is built with mandrel bent SS304 stainless steel and backed by the ARM MotorsportsLifetime Warranty.  The ARM N55 Catted Downpipe starts with a 4" diameter at the precision CNC machined turbo v-band connection.  It transitions to the 5" 200 cell sport catalyst, and gradually reduces to a flared joint to optimize exhaust flow while matching up to the stock midpipe v-band connection perfectly.    

The ARM N55 Downpipe features two O2 sensor bungs to allow for reinstallation of the OEM oxygen sensors.  The O2 sensor bungs are located higher up on the ARM downpipe to avoid stretching the O2 sensor wires during installation.  A tune or CEL Delete will be required to avoid a check engine light from displaying on instrument panel.

Flashing Our Stage 2+

 By improving exhaust flow the ARM N55 Catted Downpipe prepares your F-Series BMW for the higher boost tunes.  If you already have a software program for your N55 chances are these tune files are already pre-loaded into your software waiting for you to flash after your downpipe installation.  Most tunes require an upgraded downpipe and FMIC to run properly, if you don't also have an intercooler upgrade check out our here .  The ARM N55 Catted Downpipe will allow you to run any tune that requires a downpipe upgrade.  Stage 2 N55's can see power around 400whp and 400wtq.