2011-2012 BMW 135i, E90 E92 E82 N55 Downpipe

Circuit Werks latest Satin / Brush Finish for the BMW 135i N55 2011-2012 Turbo 4" Downpipe.  Fits all E90/E91/E92/E93 N55B30 motors from 2011-2012 perfectly with stock turbo or an aftermarket turbo using the stock V-Band Clamps. Fits all the 135i Coupes, Convertibles, and Sedans as long as it's the single turbo N55 motor.  All made out of Stainless Steel and T.I.G. welded.  If you're unsure which downpipe you need for your car, please contact us and I can verify if it fit ours or not.  Please check out our other listing for all the other BMW turbo downpipes in our ebay store.  If you have the 2011+ 335i we also have a similar design downpipe made specifically for the 3 series, 

Professional installation might be required but this is a direct bolt-on.  Comes with three o2 bungs with plugs, if you do decide not to use them.  Might not pass smog in some States even though there are secondary catalytic converters on your exhaust mid pipes.  Typical gain with a tune is around 20+ hp.  We also sell CEL Fixes separately.  

The most restrictive part of any exhaust system is the catalytic converter.  The stock catalytic converter is meant to filter the flow of the exhaust gases to reduce the amount of harmful gases into the atmosphere.  That is a potential performance restrain.  Downpipes eliminate the stock catalytic converters and reduce exhaust back pressure by maximizing exhaust flow.  This downpipe allows the turbo to spool up a lot faster and also build boost quicker.  The result brings out the vehicle's performance potential by giving it a high free flow exhaust system.