Just found this and thought it would answer some of your questions. Not sure if I'm allowed to do this and apologies if I'm not, copied it from another forum where the chaps selling the pipe. Thought the other info on the benefits would aid. BMW M57N2 x35d DPF removal downpipe Requires software upgrade, this is the downpipe only. The Diesel Particulate Filter on the below BMW models is renowned for blocking and requiring replacement at a cost in the region of £1400. When faulty the DPF causes substantial loss of power and impacts fuel economy dramatically. This is a fix and forget solution!!! Coverage 3 Series 5 Series 6 Series X3 X5 X6 E90, E91, E92 E60, E61 E63, E64 E83 E70 E71 335d (M57N2) 535d (M57N2) 635d (M57N2) X3 3.0sd (M57N2) x5 3.0sd (M57N2) X6 35dX (M57N2) March 2006 to Current November 2005 to Current May 2006 to Current March 2006 to Current January 2007 to Current January 2007 to Current Direct replacement on part numbers - 18307807474, 18307796215 Anyone throughout the UK and Europe can now purchase our DPF removal pipe for this vehicle and release the true potential of this incredible engine. Performance and economy software available up to 360bhp!!! Please enquire for details... Very Important Fitting this downpipe without the correct software upgrade will result in premature turbo failure. In order to disable the function of the DPF and align the turbo pressure to the new downpipe our software upgrade is essential. This service is available throughout the UK at a cost of £399 or alternatively the complete DIY package is available here. What's in the package? 3" Bore downpipe with machined stainless steel turbo fitting, uprated stainless flexi section, milled fittings for lambda and temperature sensors. This downpipe is a direct bolt-on replacement for the Diesel Particulate Filter and downpipe that are fitted to the car from the factory. Built for performance, economy and longevity! Performance - You will enjoy reduced turbo lag and a noticeable performance difference throughout the entire rev range, the original downpipe exits the turbo with an immediate restriction. The DPF is designed to collect the particulate matter (soot) in the exhaust and then at extreme temperatures, burn the deposits off into ash. This poses a restriction in the exhaust system and by design induces excessive temperatures which have a direct effect on your turbocharger and intake temperatures. Removal of this filter will result in an excellent improvement in fuel economy and when coupled with the performance software, the new behaviour of the vehicle is remarkable. Turbo life will be extended and turbo lag will be substantially reduced. Economy - You will experience a 5-10 mpg improvement over the original DPF depending on your driving style and software selection. Longevity - Your upgraded downpipe is over-engineered in 316 Marine Grade Stainless Steel and the flexible coupling in 304 Grade Stainless Steel, flanges are laser cut for a perfect fit and finish, your new downpipe should outlast the life of your vehicle. You should also expect extended turbo life as a result of reduced turbo temperatures. How does it fit? - This downpipe was carefully developed using the Genuine BMW factory item as a template and tested on the vehicle, improvements were made to flow where possible. Every downpipe is hand made using a jig ensuring a perfect fit every time. Noise - There is no noticeable difference to the sound of the exhaust on mild to medium throttle levels. At full throttle the whistle of the turbo is more audible. MOT - Removal of the DPF on the listed BMW models has no effect on the MOT smoke test. Your engine will produce a more complete combustion and has been tested to pass the MOT smoke test without any issues. Petrol cars differ as they are subject to a full emissions test. Quality - Our exhaust components are built with over 20 years experience in all kinds of fabrication and welding you can be assured that the quality of your new performance downpipe will be second to none!