Ok guys, think Im going to put a 3 wire heated o2 sensor in my truck. Ive seen people talking about a gm harness for the 3 wire hookups, how much is it, what is the part number, and is it needed? Also what vehicle should I get the 3 wire o2 sensor for? IS it precat, postcat, etc? Also what is the approx price of the sensor. Thanks guys. Chris.