Guys, i have an 88 euro m3 (i'm in uk) the car was fitted with cats from factory, but when the exhaust needed replacing, i fitted an o.e non cat centre section. my question is: can i disconnect the o2 sensor now that the cats are no longer in place? i'm sure i've read that some owners have got smoother running/better gas mileage by doing this. will it affect the computer/afm adversely. U.S guys: note that cats are not required in uk for pre 1993 cars. thanks for any help/ comments. Darren.