It's been eight years since I did mine but I recall American Cushion Industries having the higher quality (and price) seat padding. I got mine from NPD (C-SF-203). The first couple years they felt comfortable but I thought I was sitting high in the seat. Now, after a few years, I think it was more an issue of me being used to the low, smashed down originals. I like them now.

I did the reupholstery on my rear seat but had the buckets repaired and recovered done professionally.