So I'm going to get my cats removed or gutted, and had the car on a lift and seen 3 pipes coming off of the exhaust. Those pipes are what my question is. What are they? Should I block them off or run them into new pipe? I have 3 cats. 1 pipe is right after the first cat, another is in the second cat, and the third is after the third cat. What are they? Where do they go? What do I do with them when I remove the cats?

 

Download and study this part of the Factory Service Manual.

http://foxed.ca/rx7manual/manuals/19...ssions_12A.pdf

 

I'm fairly certain the first 2 pictures are air injection pipes that attach to your air pump. They help the catalytic converter operate properly, and therefore will be of no use if you remove the cats.

I'm confident the last picture is a temperature probe. It is tied to a warning light on your dash that indicates if your exhaust is overheating. I'm not sure if it works properly when the cats are removed.