I also completely relied on a Dremel tool with remote cable drive and plenty of cut off wheels to get manifolds off my '97 5.4. Luckily, only broke one stud. After years of heat cycles here in the Northeast,
they rust into one blob. The nuts no longer have any shape for any kind of wrench or vise grip to grab.
There's no room for a regular air tool/ grinder to reach and you've got to be careful with the torch. Only advantage is that, compared to my '05 three valve heads in 2nd Gen, there's alot more room to work. And there is more abundance in aftermarket stainless shorty headers, which is the way to go with replacements, along with stainless fasteners that the factory should have put in to begin with. I dread the day when I have to do this to my '05. And, there seems to be only one Gibson SS shorty available for this engine and it's over $700 bucks.