Mods?......
Like all have said, there isn't a whole lot you can do to the 717cc engine.
The easiest and less costly to maintaining a modded engine is to make changes to your pump.
There are pump wedges that will lift the nose a bit and allow for a bit more speed, intake grates that will give you quiker hook up and sharp turns without cavitating. Impellers that you can use to give you a little more speed.
The 717cc engine has 85 horse power with 35 horse power at the pump. The engine is reliable but not much on power. The best way to see more speed is buy another ski with a bit more umph........:cheers: