cats

gutting my cats, straight piping all the way back leaving my stock muffler on for part of my sleeper appearance, and hopefully i get my loan and im gonna do sum engine work and put a rear mounted turbo so ppl cant see that when i open my hood

I think gutting the cat is a bad move. You can purchase a high flow cat that will accomplish basically the same thing for a few bucks and the car will probably perform better. Otherwise you will need an O2 simulator for the back sensor and if you have emissions testing in your area you will have to reinstall it each year. You can make a car a sleeper but keep it legal at the same time.

I agree with GTP. Totally gutting the cats will mess up the catalyst monitoring oxygen sensor's signal to the ECM, and could actually cause a reduction in performance.