Same issue with mine, although it isn't because it's a "low grade" foam is it has been alluded to in this thread, just a firmer foam than the original ones FoMoCo used. While I do find the higher seating height a bit of an issue, I also find that the TMI foam is far more supportive than the originals ever were.
Doubly crappy for me, I bought the CJ Pony Parts seat track extenders for my drivers seat and along with the added 6" of leg room, it bumps you up another 1/2-3/4" on top of that. My head was practically sticking through the sunroof.
The only real solution is to find a way to drop your seat brackets a little. I've cut and rewelded my seat frames to help this, but It seems I still haven't gone low enough. Gotta find away to get another inch or so lower.
I haven't seen, or heard of the drop brackets
@madspeed was talking about, but I'd be interested in a set if they do exist.
How tall are you?
I'm 6'3" and even without the seat track extenders, my head is touching the frame of the sunroof. One good pothole is going to give me a concussion.