Robin there not massively expensive if you buy the cloth ones like mine I paid £369 ish each for the seats and £150 each for base frames and £50 each for side mounts. The support they offer is amazing really helps you drive hard, they are very comfortable seats even for me and I'm not thin by any stretch of the imagination lol. I love your idear of having the cushion done in interlagos. Robin if your ever in the southampton area your welcome to have a little sit in the seats :)