Cats get hotter with a rich mixture, my car is only rich at wide open throttle, not all the time, the wide band I am using is NTK, I am putting a flex fuel set up on it & this one is tunable & data logs with the wide band input, Baily's Hyperformance sells & installs this set up & they are very well known in the gen III world, Eflexfuel.com the Pro kit is the one that is tunable ONLY the fuel is . should pick up some power on E85 we will see