I've got a 2006 Maristar 200 SS that is pretty much salt water series X-2. My boat has the 5.7 Crusader which I really like for the ease of doing routine maintenance. I believe the salt water boats also get stainless hardware in addition to the above mentioned upgrades. Built in flush system is nice for running boat up to temp out of water for changing oil. Salt water is tough on billet aluminum-one thing to pay attention to when looking at a salt water boat.
2006 Maristar 200 SS