hey I wanted to remove my cat for race purposes and was wondering what problems could develop form doing that? Since the ECU does take readings from the o2 senors right before and after the cat. Don't worry the car will not be seeing any street use only track. What will I have to do if I want a straight connection from my hedders to my muffler? do I just let the shop cut off the cat and have the o2 sensors in the same position? Also this is not going on my M3 but a project honda, but since machanics are about the same for all cars I thought I'd ask some of the really knowlddgeable machanical guys on the net I know. thanks for any help you guys can give me.