Exhaust Leak

So I tried the infamous seafoam the other day on my 98 4.0 to try and get rid of my slightly sluggish low end. Got a little smoke, not much, but I noticed it was coming from my exhaust/intake manifold area. So Im fairly sure there is a leak there. So before I tear it all off and replace gaskets, is it plausible that this is contributing to my loss of power and slightly lower gas mileage? ? Or should I not particularly care if I have a slight leak? Just trying to save myself some work if it's not necessary. Thanks.

does it knock? If it is not giving you any problems I wouldn't bother replacing it.

anyone have a good muffler replacement write-up??

I'm attempting this on sunday. my concern is getting my completely rusty 10 year old muffler off of my completely rusty 10 year old converter without destroying the pipes on the cat.

anyone?

bumper