Stu - yeah I thought about that but they are kinda pricey. What advantage would I get over two Magnaflow cats (about $800 installed)? Would it even work wit non-M exhaust? Why are you selling them, what do you run?
Betty - I have done the same. Kept all 4 sensors. There are 4 wires going into each sensor. I only cut one wire per o2 sensor - the signal wire, connected it to the o2sim output.
I really don't understand why I ended up with heater codes.
Screw it, I'm tired of the smell (the car also runs a bit rich so it stinks even more). I'm putting cats in.