[Chard]

I've searched some more about this and read that some people are plugging the rear o2 bungs and hanging their rear sensors somewhere under the car with success. Can anyone confirm that the rear O2 sensor doesn't affect fuel mixture? That doesn't sound right to me...
I'd hate to try this out only to find that the car runs worse than stock.

Another consideration is getting an aftermarket sport cat but putting it further down the system, basically near where the 2ndary cats are, and hooking up the O2s there. Isn't that how the RoW exhausts are setup? Where could I get extended O2 sensors?

It sounds like regardless of CEL, the catless headers will yield a slight performance gain but will yield even more if paired with a RoW tune, correct?