[BMW Atlanta]

Did you apply any kind of thread dope or antiseize to the threads of the O2 sensor? Perhaps getting it on the probe and damaging it or pulled one of its wires out from twisting or tugging? Or perhaps the cat code plug needs to be removed? Or jumper installed? But youre on the right track with re-synching the TB's. Anytime you make a performance enhancement or change they should be adjusted. I had to re-synch going from my Z-Technik to the Laser Race exhaust.