I've fixed dozens of these. Well, 52 according to the remaining stock of TimeSert kits. The problem exists from the 97 through 2004 model years, and can be in any of the V8 or V10 engines. I have given away a few of the inserts.
The repair kits are a little scary, but I've never had one not work out. The whole Triton line, and its close cousins are good reliable long lasting engines. I wouldn't let the plug fiasco steer you away from a vehicle with one of those engines. Personally, I'd be more afraid of exhaust manifold leaks. It' more money and hassle to fix, and seems to be more common at this point in the life of engines that old.
When working in the Romeo plant, trying to help with piston slap issues, I was told that the design with less than 5 plug threads was engineering that was handled by the same group that worked on the exhaust studs. I don't have any proof, but its a cool old rumor. Maybe there really is just one guy that needs a good swift kick.