I did a search on this and really did not find the answers I was after so here goes.
My 2.4 has a exhaust leak from the Y-pipe junction (header to pipe). I tighten the nuts, which were loose and replaced the two donuts. It started again and found the nuts loose again. I wnat to use loctite but am afraid I may never get the nuts loose when I want too. Anyone else have this trouble, and did you come across a good fix?

 

I can't say I've had the problem, but it seems to me that unless you plan on replacing your exhaust any time soon, then you should lock-tite them and take your chances later. They might make some high temp stuff, I can't remember, but at worst you could just cut the bolts off if you ever needed to.
My exhaust leaks closer to the tail pipe.

Erich

 

I don't have the stock manifold anymore, but where my header connects to the cat, I have a flange. I replaced the stock bolts witha set of stainless steel bolts, nuts and split lock washers. They hold nice and tight and I've not had any trouble with the loosening up.