RE: Saltwater maintenance
You will have to get both the bottom and the outdrive painted with antifouling paint if you leave it in salt water or you will have a barncle/growth farm there. Find out what paints other boaters in that area find effective. For the outdrive the only thing available is Trilux for aluminum but you have to put the barrier coat (Primocon) on the drive first. If you have a speedometer pickup and a transom mount transducer you need antifouling on them too. The main thing with the outdrive is maintaining the paint protection and the zincs. Find out if there is stray current in the marina, you may need more zincs or a galvanic isolater system. I have left my OMC Cobra in the salt for our season (May-Nov) for 3 years with virtually no corrosion, but it is not a marina with boats hooked up to shore power. You will have to have the drive serviced every year for it to last in salt esp, but it can be done if you are diligent. You will need to wash and wax the hull more often as was noted. Make sure you auto bilge system is reliable before you leave any boat in the water. Coating the engine with a corrosion block ( I like Boeing's Boeshield) is a big help. Main thing is the outdrive maintenance. They are fine if you keep up on them but bad if you don't.
BTW, is this a closed cooling system?? That is best for salt, if not, if it was run only in freshwater, I'd also install closed cooling before running it in salt. Otherwise, just flush it when you can.