O2 sensors

[poxtomod]

I own a 95 eaglle talon esi that i am converting over to an eclipse gs, and recently bought a full exhaust/ with header setup. The new exhaust has two O2 sensor locations, but my old one only had a single sensor(right near the header). I am wondering where the second one, which starts at about the cat, hooks into the engine, any help in finding this would be appreciated. I tried searchig by using the first as a guide and got no where.
My car should have two sensors right? I live in Canada and know american cars need exhaust work to be imported over here. It has also passed an emissions check when i bought it which adds to my confusion. I dont understand how it would pass the test with missing components.

[ez1286]

Wait are you converting to a gs or gst? The 95's nt's may have had only one o2 sensor if they weren't obd2 but i think they were cause the turbos were.