I have to agree with Foster...seats are extremely hard to find!! I just bought a speedster200 and on the way home there was some crazy cross winds across the Tampa bridge....all of a sudden I see one of the seat cushions fly out of the boat!! After dropping off the boat I went back to see if I could find the seat, luckily I found it on the side of the highway but it was totally destroyed. The next day I called the local dealer to order one (Babbitts online had them listed for $175) they priced me $220 so I told them to order it, I get a call back 1 hour later...the dealer called BRP and found out they don't sell seats/ cushions anymore!! I tried bringing what I had to a local upholstery...the guy laughed when I walked through the door and said come back in 2 days!! He ended up calling me the next day, the seat was just as new and he only charged me $75!!
Anyway, sorry for the long story but if you have the original seats get them re-upholstered...if you don't have the original seats you may be SOL unless you find a guy parting out his boat.
Good luck..