on the 3rd and largest cat on there is a pipe leading out on my na.. thats goes to the aux ports right? so i need to just cut it off and forget about it if i am wiring them open, thanks!

 

You're partially right...That is your fresh air feed for the cat from the air control valve.

The feed for the aux ports comes from the same source basically, but the supply nipple for it is further up the split-air pipe...

 

So if you're in an emissions testing area you can't remove it, or must be able to reinstall it for inspection if you need to.

 

also if you run that cat without that pipe you will destroy the cat