I would replace oil, oil filter, coolant, gas, spark plugs, and make sure battery is good. Supercharger will have to be inspected as well at some point, but as long as you aren't running it full throttle on the water, it should be ok. Make sure you start with hose NOT going and turn it one once you get the motor running if you are on land. Shut off water before you shut off engine. If you can get someone to pull codes with Candoo or BUDS before you start, that may be helpful as well, but not vital. That is all I can think of. I am sure the smarter members will chime in with more specifics that I have overlooked.