Well, i'm in the market for a stand up and have a few questions. I have been pointed in the direction of the Kawasaki 550 as people say they are reliable, powerful for what they are, and cheap. They go from 400-900 around me. I have kind of rulled out the 440 because i'm 200 pounds and what to have something with decent power. I know the 650 would be nice, but i'm not wanting to spend that kind of money. 400 is what I fee comfortable spending on a summer toy. My questions would be how fast does a stock 550 run? And also, I see different models on craigslist....JS, SX, etc. What is the difference between these? Any answers are appreciated, so thank you ahead of time!