I paid £300 for the pair direct from corbeau and for that price there a bargain come with runners and side mounts however I have had the squeak from the seats and I think it's from the runners and not the actual seats, not much adjustability in the side mounts either but at that price can't complain, for the female part of the seatbelt I just drilled another hole in my subframes to mount them although I will be getting harnesses at some point when I sort out a cage.
Great pics and info
Had them in long ? Does the material seem like it will last; bearing in mind these might well be for daily use and not just for races at weekends !!