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AR Design 135i / 335i / 335xi 4" Catless Downpipe N55, 2011-

  • Sale
  • $729


We are thilled to present our new 135i / 335i / 335xi 4" Hi-Flo™ catless downpipe for the BMW N55 engine! The only 4" downpipe currently on the market! In addition to an intoxicating and exotic sound, these downpipes add significant power and virtually eliminate turbo lag!

Our Hi-Flo™ 4" Catless Downpipes Feature:

  • The only 4" catless downpipe currently on the market! Built with a carefully made 4" to dual 2.5" collector that mates to the factory style exhaust.
  • Typical gains with tuning in the 20+hp range!
  • 100% hand crafted in the USA from premium 304 Stainless Steel - flanges and O2 bungs included!
  • Water-jet cut 304 Stainless cat-back flanges, and CNC'd 304 Stainless V-Band flange.
  • 100% TIG welded, argon back-purged.
  • Set of our exclusive bomb-proof exhaust gaskets included.
  • Grade 10.9 Metric Hardware (145,000PSI tensile strength, C32-C39 Rockwell, Zinc Plated), and Nord-Lock positive locking re-usable washers included.
  • Factory location O2 bungs, with an added bung for a wideband O2 sensor!
  • Lifetime warranty against any manufacturing defects given to original owner.
  • We do NOT grind/polish our welds as some other manufacturers do. Grinding welds compromises the strength of the weld, and can lead to weld failure! Especially critical in applications exposed to temperatures in excess of 1200°F. Such temperatures will  also rapidly deteriorate the polished finish.