Ive done some light research on the fourms but still a little unclear with all the responses ive seen. Long story short i now have gutted cats and have been babying my t as i am scared of afrs being outta wack. My cortex shows me 02 stats but im am somewhat unclear of them because i wont do a WOT run. Someone posted on a thread that gutting there cats didnt change there afrs at all. My question is due i need uprev now to be safe or can i get away with a different tuner and still run tunes and be safe?