I got a cstom exhaust done true duals all the way into borlas on the back. No cats at all! I completely removed the o2 sensors there are 4 total. I disconnected them. My question is if I can do this without doing any harm? I have a chip programmed for no o2 sensors. Can I keep them off completely by disconnecting them, or do they need to be connected and tied up somehow? By the way i go 2.25 inch exhaust. I will go to the track on thursday to see if this exhaust setup makes a difference.