For those wanting more power and better sound out of their BMW 135, it is easily obtained with the Agency Power racing midpipe. The midpipe is designed to be modular with your stock exhaust system. You can use this midpipe with the factory downpipes or factory muffler system. It also goes perfectly with the AP rear muffler section! The full stainless steel midpipes are specially built in-house by Agency Power using their mandrel bender. The dual 2.5" 304 stainless steel is all TIG welded to the CNC machined flanges and the high flow resonators give you an incredible tuned sound. To mate up at the stock muffler location, the midpipes feature a merge collector into a 3" stainless steel tube for optimal exhaust flow. This midpipe is designed to improve your cars performance by reducing back pressure caused by the restrictive catted midpipe. The Agency Power midpipe is a bolt-on product that does not require any welding, cutting, or other parts.