You got the Ski for a great price, find out how much the Bolts and valves cost, if reasonable then replace them and you can put a slightly higher boost impeller in the Super charger.
They have blades that can give more boost lower down or higher up, depends what you want to do with the Ski, Speed or towing or both.
I got my Ski for a little over $3000 less than they were selling for with low hours and so I spent $3000 doing some improvements and mods.
All that I did improved fuel economy and handling as well as engine reliability.
I also now get 68mph with two people and haven't changed the revs of the engine.
I can get a tune and boost revs to 8K or 8.5K and get a huge boost to top speed.
I mainly wanted reliability and if the things I did also improved economy and performance then a bonus.
Also what you need to look at is, how much would you have spent on a good reliable Ski and how much would it cost to replace bolts or Valves if they do let go ?
It's normally cheaper to do it before anything breaks
Well it has been for me as a Valve bouncing around inside a cylinder normally doesn't improve the piston to much and if the bolts on a flywheel shear, I can only imagine how much good it would do spinning at 7K as it lets go as I am sure it wouldn't shear at low revs ?
Probably as you jump a wake or wave and land with the revs high as you forgot to decelerate as you launched or started to accelerate before you hit the water ?
They are easy enough to work on and if you enjoy working on Engines and such as I do then it's also fun
Hope you get a ton of fun from your Ski