This BMW M235i performance exhaust is made in 3"/76.2mm pipework and fits from the turbo to the centre exhaust to replace the standard catalyst. The sports cat exhaust option will enable you to pass a UK MOT emissions test or police road side checks. The de-cat sports exhaust option is sold for motorsport and off road use only and will NOT be able to pass a UK MOT emissions test or police road side checks. All relevant fittings and gaskets are supplied.