HIGHLIGHTS • Gain up to 23whp/29wtq• Faster Turbo Spool• Improved Exhaust Sound• Upgrade to Stage 2 Tuning• SS304 Stainless Steel  PROFILEAn F30 N55 Downpipe is regarded as the best hardware upgrade to get the most power from your N55 powered F-Series BMW.  The stock N55 downpipe comes from the factory with a catalyst that severely restricts exhaust flow.  Upgrading your downpipe unlocks power, improves turbo spool, allows you to run stage 2 tuning, and increases the exhaust note of your N55 powered BMW all at once.  An N55 downpipe upgrade is the first hardware upgrade every N55 owner should invest in.   ENHANCE THE SOUND OF YOUR N55The M235i in the video below is only equipped with the ARM N55 4″ Catless Downpipe, it is otherwise on a 100% stock exhaust.  The car has never even been flashed, it is on the original DME programming from BMW.  The ARM N55 Catless Downpipe will increase the overall volume of your BMW, open up the exhaust burbles even on OEM programming, and make the turbo spool significantly more audible. CONSTRUCTIONThe ARM N55 Catless Downpipe is built with mandrel bent SS304 stainless steel and backed by the ARM Motorsports Lifetime Warranty.  The ARM N55 Downpipe starts with a 4″ diameter at the precision CNC machined turbo v-band connection 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 STAGE 2  By improving exhaust flow the ARM N55 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