Leave the stock Sensor in place, or replace it with a three wire. Go appox. 36 inches down from the turbo outlet and install a bung in the exhaust pipe on top of the pipe or at least at a 45 degree angle so as not to come in contact with condensation in the bottom of the exhaust pipe to install your AFR gauge sensor. This hook up shows you what the wideband AFR gauge is reading in real time without screwing with the ECU.