honestly, I have found only 2 oxygen sensors so far...

 

only have 2 lol

 

I just replaced mine. you have 2 o2 sensors, 1 before the cat and one right after it, i got my sensors from o'reillys for 50 a pop (thats what a discount from NTB) what happend was i sliced into the o2 sensors to find a wire to hook up my a/f gauge, i guess it was to much slicing and my check engine light came on, so try not to cut them at all.. i put on my new sensors and cut BEFORE the sensor in the harness and everything works fine.

I got the Bosch Sensors, they look very sturdy and good quality, and so far with mine ive had no problems, Bosch makes ****ty plugs for our trucks, but some things they make are actually really good.

I would go with Bosch if i was you, and if you got a jack and like to get dirty then its a DIY job, all you need is a 15/16 wrench (thats what i used) and the new sensors and thats it... They screw out of your exhaust and clip off at the harness... i did mine on a floor lift at NTB and it only took me about 5 min to chane both of them out. The only thing that sucked was the Upstream sensor is clipped on to the top of your tranny, so you have a blind spot when un cliping the harness. Other then that it was all good for me.

Also you will need 2 sensors.

Upstream (before cat)

and

Downstream (after cat)

They look the same, but have diffrent model numbers, im not sure if it matters where you plug them, but i would play it safe and get the numbers right.