My 2c.....every after-market seat I've ever seen, was designed for a sporty look, or for competition of one sort or other. None were designed for comfort or long drives......particularly for people with back problems.
When I got my '06 SES with leather seats, the lumbar area of the rear cushion just felt awful. I think one of my first mods was to remove the rear seat cover and add a one inch thick 12x12" foam pad in the lumbar area. The difference was/is amazing. I have no problems with that seat any longer.
I went to FF this past week end.....but had something going on Sunday. So I drove down early Saturday, left FF in the early afternoon, and drove straight back to St Louis....a round trip of almost a thousand miles in about 22 hours. I've got a bad back. Felt no pain at all with the modded seat. I don't think I could do better than that.
I'm a little under 6'5"...240.