first of, water test it! that tells you everything! but considering your in new york, figuring water is still too cold to ride, have him plug it in. take seat off, let engine run, press throttle few times! check if it accelerates and decelerates normaly, as well its got 110 hours, supercharger was either rebuilt and if not, it will need to be rebuilt! ( thats a must). check that the dash ( analog) works fine, and take a look at the engine bay make sure nothing seems crazy! otherwise considering this time a year. since you cant ride it thats the best you can do, there is more specific stuff to look at but the other members who know more then me will tell you all about it!!! as for reliability! from personal experience seadoo last very long! look at all the 90's seadoo still running! and as for the price of 6200$ from my region, would seem fairly priced as for your region im not too sure!