I don't know if I will nead the manifold gasket...but you should replace the donut. I just both to be safe, because it would suck to need it and not have it. Plus they came to like 30 bones for both and besides...if you don;t open it...you can always return it !
i didnt replace my gaskets but im going to when i have time cause i can here a small exaust leak from underneath but no big deal my trucks loud as hell so you only hear it for a sec. Whoevers going to do it you can use some of the pieces from you jack under the seat to bust it up thats what i did and used a big screw driver. i think that huge ball of cotton is the hardest to get out.:mav:
sure youre not just hearing the air in the cat? it sounds like a leak, but on mine its not. i had it all checked. they can weld a straight piece in the cat for you to delete the sound, but it sounds good on a 4 banger...i think.