At the time I couldn't find a good firm foam like I wanted. So, since I was forced to use a softer craft foam, I actually used something closer to 3-3.5" figuring it would crush down to around the 2". It's lasted a year and is getting close to needing redone. When I redo it I'm going with something a little heavier than what I used before and will go for 2-2.5".

A better grade material will last longer certainly... I got what I paid for. Of course, I'd kill to have the seats out of my old '01 1500 back....

 

How about cramming one of those memory foam things in there? Would that work?