When you are doing 150 MPH at a track, going down the straightaway, and you have to brake at 100% to make that 90 degree corner, with your five or six point belts holding you from sliding forward, you "submarine" in the seat. (Notice that phenomenon whenever they show race car drivers inside the cockpit in that situation.) To prevent that, the bottom seat cushion has to be firm, firm, firm, so it doesn't crush readily. Hence why I heard Tadge Juetcher and interior Design Manager Ryan Vaughn both say that the bottom foam cushion on a competition seat is much firmer than on a GT seat. I also heard them say at the Bash at the National Corvette Museum, that if you need to sit in the comp seat to determine if they are comfortable for you personally -- as the side bolsters are larger and do not move outward. Finally, talked with the C7 "Body Manager" at the Bash about this and he said, looking at me (I am 6'0", 160), that I'd fit easily, but someone my height who weighed a lot more, depending on how much more, might not be comfortable sitting in a comp seat. Finally you also have about four month delayed availability with the comp seats.