I have test pipes and I never have a CEL light on even when I have had problems and codes stored. Is that how the X chip works or is their something special about how the O2 sensors are mounted. Even if the o2's are diff why no light at all? The light does work when you 1st start the car.

P.S. For those who don't know already I bought my car with the mods at an auction.

There are mods that you can do to trick the ECU in thinking that the O2 sensors are connected and working. I think it involves connecting a resistor to the sensor wires, or something like that.

Haven't run mine without cats, so I couldn't say if the s/w is compensating or masking.

special bungs to push the O2 out of the stream of the exhaust.

I am going to try this on the weekend, hopefully it works!