The Beard Superseat will fit - just barely. ATVR uses these seats, but actually narrows them a little, however a standard super seat, not ultra will fit. It makes it tight for the gearshift, and I actually moved it over a bit by bending the tabs slightly. Corbeau also makes a Baja SS seat, which is very nice and only about $160. The beard seats cost about $250. When doing some research myself on the seats I ran accross this manufacturer of seats and thought that I might try this one instead of my Beard seat.
www.racecraftseats.comOnce you sit in a racing seat like that, you just can't go back to the stock one - IMHO.