Our 5" Super Sports Cat made to fit the legendary BMW B58 features a 200 cell catalyst to ensure your vehicle will pass MOT and will not activate the EML light. This pipe is massive, the 5" tube that gradually steps into the 4" flexi pipe is the biggest pipe combination available on the market today for the B58, this ensures maximum, uninterrupted flow to match that of a full decat downpipe so there is no longer a compromise on power when choosing a sports cat.