Parts....
Although the Utopia you are looking at is a nice Sea-Doo boat, you will fall into another class of distributers due to the Mercury engine. There is no one answer on who all the parts distributers are. Like e-bay, people look and compare from a big variety of shops. I do know that Babbitts is one of the top sellers. And for the Rotax engines, SBT seems to be a leader. But then again, these distributers will have a limited use for you and the Utopia. You will be able to find parts for your hull at the same places any Sea-Doo enthusiast buys and SBT may have your impeller.
That's about all I know off the top of my head.