I am considering a Catless down pipe for the R58. I know a tune can prevent a check engine light from coming on due to the second O2 sensor, but I already have a RMW tun on the car and unless I have Jan do a new tune I don't want it messed with. Once I do more to the car I may have a new tune done but not for a down pipe. Has anyone used a spacer when removing a cat with good results? Or does anyone know of another way of preventing the light from coming on? Detroit Tuned has a has a Milltek down pip with a hi flow cat but I think I would like the Catless Milltek. They also sale a Vibrant O2 extension. If I get the catless down pip I plan wrapping it and getting a turbo blanket. So any thoughts?