ARM Motorsports new N63/N63TU Catted Downpipes for the 4.4L V8 Twin-Turbo powered 550i allows you to take your N63/N63TU engine to the next level. ARM N63 Catted Downpipes feature high-flow 200 cell ceramic sport catalytic converters positioned in the OEM location. 

Made with full 304 Stainless Steel and 3" construction these downpipes provide a significant increase in power and torque over the OEM catted downpipes. In addition to the massive power gains, these downpipes open up an incredible exhaust sound from the turbocharged V8!

By replacing the OEM downpipes with the ARM N63 Catted Downpipes, you'll be removing the restriction from the OEM converters.  This will reduce exhaust back-pressure and allow the exhaust from the turbochargers to flow more freely. This increase in exhaust flow allows for the turbos to spool faster, increasing power and torque throughout the RPM range of your N63. 

Tested on an N63-powered 2012 550i GT xDrive with a Stage 2 tune, the addition of ARM’s 3" Downpipes and Cold Air Intake yielded +48whp and +43wtq, raising output to 460awhp and 525awtq. The catted version maintains nearly identical gains compared to the catless setup, while offering the benefits of a catted exhaust system.

Features:

• Gain up to +43whp / 48wtq
  
• Improved Turbo Spool
  
• Aggressive Exhaust Note
  
• 200 Cell Sport Catalysts
  
• Direct Bolt-On, Fully Reversible

What's Included:

• 2x ARM N63 3" Catted Downpipes
  
• 2x ARM Crush Brackets
  
• 1x Hardware Kit