Which O2 sensor for a Haltech Termed harness.
 

Well, now that I have my Single turbo up and running (YAY), I need to do some fine tuning on the idle, throttle tip-in ECT ECT.

My Harness did not come with an 02 sensor, but it is pre-wired for one.

I need to know which one to get.

I have a 3 wire Weatherpack connector. Im guessing its some generic GM sensor,

So what should I get and where should I get it.

No reason to use an narrow band o2 sensor at all.
Just buy a wideband and do all the tuning with that.