I have ls1 edit. Yes you can turn off the rear 02's Also can do just about anything else with it. Infinite ways to screw up the car. I removed the VATS, skip shift, rear 02's and what ever remaining emmisions there were left. You can also change the rev limiter settings and remove the top speed limiter. The tuning options are mind boggeling for me so I'll pay some one to do that once I get to that point. Mark