I have the Bassani X pipe that you can change from catted to off road fairly easily. I am think of switch to off road tomorrow. The impression I am under is that by doing this a CEL light may come on and that I can shut off the rear O2 with my SCT tuner to solve the problem. I have no experience in using the SCT tuner as I didn't actually see my tune get loaded into my car. Can someone tell me how to turn the rear O2 off via the SCT X3. Thanks! Bob