Here 'ya go...this is from the Ford guys , hard core Fox body & later 90's+ up OBD2 , Mustang drag racers forums. A lot of these guys use various brand name headers, X pipes, all with cat deletes (ONLY for off road use of course)...with the following circuit >>excellent results, and NO c-e-l s
PLEASE don't pm me , I didn't invent this...just found it and passing it along here. There is even a Co. Dallas Mustang that makes a "Plug-in-play" version of this circuit, but the plug in ends are spec: Ford and will not interconnect to the BMW lower O2 plug end design.
Radio Shack usually has these in their self serve drawers, if they are out just drive to the next outlet. I've tried this circuit out on the 3.0 Mazda6S with race headers, y-pipe, downpipe with good results.