If I hog out my cat, what will the O2 sensor do? Will it make my car run lean/rich? How hard is it to remove cat on drivers side manifold?

 

You'll have to take them to an exhaust shop and have them cut out and went in a pipe. I did that on my 97 with dual cats. It cost about 50 bucks.

As for the sensors, I think you gonna have to get the comp reprogrammed and have them deleted or you might throw a code. Im not sure about that, hopefully someone will clarify.

 

I believe that any adjustments to your cat will not cause any change in air/fuel ratio. The O2 before the cat determines that. (Later years have 02's before and after the cat )

 

Since you have a 96 with OBD2...you will have to keep your pre-cat O2 sensors in place, and get O2 sims for the 2 post-cat sensors.

 

Probably won't do diddly for performance at your level of modifications.

 

Is my car only a single cat? What's the coffee can looking thing below drivers side manifold? Should I need 1 or 2 sims? Both my cat and muffler are single inlet/outlet.What does a comp. re-prog. cost?

 

You are a dual cat car. You will need 2 oxygen sims.