First off, invest in a PP 6.4 chip and switch. Set you back $50 for the chip, and $200 for the switch assembly. If you already have a jump switch, you can cut the $200 down to about $50 I think. Between the speed changes and the software upgrades, its truly a necessary change.
Make sure you change your oil every 50 hours or so.
Make sure to check all the moving parts in your throttle and steering system every few months to make sure they're moving smoothly. Nothing worse than getting stuck in the middle of the lake because your steering cable or throttle cable snapped.
Be prepared to change you risers and manifolds every 500 hours or so.
Definitely follow KState's call on changing your impeller every year. Its amazing how easy those things go.
Finally, remember to check your water filter every time you go out. Only takes 30 secs to dump out any grass or debris sucked in there. Keeps the engine running nice and cold.
One last thing, don't forget to watch out for your trailer and keep up all the proper maintenance (tire pressure, hubs, bearings, lights, etc.).
Enjoy the boat. It looks beautiful.