ok, I replaced the sway bar and while I was under the car, i noticed the Stock down pipe and cat are welded. So now to cure the power surgeing problem on cold start up , Bio suggested i change out the cat. Can some give me a direction and inventory of what i will need to replace the dp and cat. I'm looking at the dp and cat welded from summitt 2.25 I/O

Thanks for your help
L8TR