Whether its a good idea or not, this is what I did.
My O2 is in the bung right after the turbo. I have an EGT in the stock location(passenger side manifold). So I bought a Legacy Turbo O2. They are desinged to be after the turbo. It however is a 4-wire. So I wired Signal and Heater wires as they should be and put the forth wire(ground) to engine ground.
It seems to be working.