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BMW E Series 135I/335I/335XI N-55 Catted Downpipe

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We are thrilled to present our new 135i / 335i / 335xi Hi-Flow catted downpipe for the BMW N55 engine! The only downpipe on the market with a large 5" body heavy-metal catalyst.  These downpipes add significant power and help eliminate turbo lag.

Our Hi-Flow 5" Race-Catted Downpipe Features:

The only catted downpipe with a 5" heavy metal catalyst currently on the market! Built with a carefully made collector that mates to the factory style exhaust.
Typical gains with tuning in the 15+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, additional bungs for a wideband 02 sensor available.  
Available with a 2000°F ceramic coating. Coatings come with a 3 year warranty against corrosion and rust to original owner.
Lifetime warranty against any manufacturing defects given to original owner.


This product is intended for off-highway application only. Installation of this part on a vehicle that is driven on public roads may violate U.S. and Canadian laws and regulations relating to emission requirements and motor vehicle safety standards.