I have a 2005 Speedster 200 with twin 155HP Rotax 4-Tecs. Reliable? Yes. Rotax is a good engine. Is the one you're looking at supercharged? If so, check with the owner to see if they have been rebuilt in the previous 200 hours. If not, then count on rebuilding them, which includes a couple hours inside the cramped engine bay pulling them, sending them off for rebuild service to the tune of around $450 each (GREAT service from PWC Muscle, though!!), and a couple more hours in the cramped engine bay re-installing them. As far as acceleration? When you hit the throttles, the boat will stand up out of the water and be on-plane in a couple seconds. My top speed is somewhere around 40mph......I must admit I was expecting faster, but 40 on smooth water is moving at a good clip, and really all I need. Biggest problem I have? Porpoising. In slightly choppy water, you won't go much past 25mph before she starts bouncing. It's almost to the point of being a deal breaker for me. Considering selling her and getting something more stable on the water like a center console. In smooth water she is FUN to play with! But on a busy weekend at the lake....like it is most every weekend in the Summer....it can be annoying.