OK, so here is my dilema. I have had my car w/ aftermarket header/DP w/ high flow cat/ and catback exhaust for a very long time. All this time, I have had a CEL for cat efficiency low. So, I am trading my car in, and was having the stock exhaust put back on. I took it up to my mechanic, and gave him my stock DP/cat and original exhaust. Unfortunately, I lost the stock manifold/header so there is a pacesetter on there, and I thought he could just hook the stock DP/cat up to the stock exhaust, while leaving the aftermarket header in place. Well he just called and said thats a no go. Dunno why, but he said it doesnt match up.

So I have 2 questions.

1.) i remember reading about relocating the O2 bung thing, and it would eliminate the CEL. How exactly is this done, and is it easy to do, can I tell my mechanic what to do? I dont think my aftermarket cat/DP had 2 bungs, only 1.

2.) I guess this is a question I should give to my mechanic, but can the cat be welded off of my stock DP, and put on the aftermarket DP? Will this get rid of the inefficient cat CEL error, or is it possible my aftermarket header is pushing too much air, and theres no way to get rid of the cel without puting the stock manifold back on?