Seat Bottom Foam Replacement Opinions?

[muddpile]

Just curious who all has replaced their bench seat foam, and what the opinions are? I had my bench re-covered and the foam patched 2 years and 7000 miles ago. The upholstery guy warned me it was shot, but made it look good to re-cover. It was nice for the first year, sucked pretty bad in the second year, and now here we are in year 3 and it's TERRIBLE! Has anyone had any horror/success stories of buying any anywhere, or what has anyone done? I would like to buy off a truck vendor if at all possible, just something I can Hog-Ring in with no trimming. Any help would be great. Thanks!