The Downpipe Kit fits in to the n20 engine: BMW 125i F20 / F21 BMW 220i F22 / F23 BMW 228i F22 / F23 BMW 320i (x) F30 / F31 / F34 BMW 328i (x) F30 / F31 / F34 BMW 420i (x) F32 / F33 BMW 428i (x) F32 / F33 / F36 Replacement for OEM BMW Part# 18327645666 from year of construction 10/2012+ 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 200cpi catalytic converter connection diameter 105mm 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.