Seedoya is correct. The 98's are not SK models. 98 came with 2 787 motors. The 99 is the SK boat with the 2 717's. Kinda odd how they made the 99 the SK. Since the SK designates it as a ski friendly boat, but yet they downgraded the engines.
also... $5k is too much. if it's very clean, with 2 new engines, then $4k would be ok. I have a 95 speedster local to me going for $2500. clean and recent engine rebuilds.