The Downpipe Kit fits in to: BMW M135i(x) F20 / F21 till 06/2013 BMW 335i(x) F30 / F31 / F34 till 06/2013 BMW 435i(x) F32 / F33 till 06/2013 Replacement for OEM BMW Part# 18328603875 made out of high quality stainless steel 1.4301 (SS304) 100% perfect fit, replace OEM less thermal load on the turbocharger more power by reducing back pressure significantly more torque 200CPSI catalytic converter connection diameter 105mm Error display in the DME possible. Catalytic Converter Disclaimer It is to be noted that Wagner Tuning catalytic converters are intended to be used on OEM vehicles to optimize performance. They are NOT intended to be used in conjunction with an ECU tune. Wagner Tuning assumes no responsibility for damages caused by modifications made to a vehicle such as, a tuned ECU and/or 'burble' style tunes. Wagner Tuning is also not responsible for damages caused by engine malfunctions creating rich/lean conditions that are detrimental to the catalyst. A warranty audit will be performed on any claim regarding a catalytic converter. In order for a warranty to be honored, Wagner Tuning will require the purchaser to provide proof that the engine was unaltered and tuned to the original manufacturer's specifications and maintained in proper operating condition. The end user assumes all responsibility regarding the legality of use of a non-OEM catalytic converter on their vehicle for the region in which it is used.