George - A really good belt that is 1/2 the cost of the factory belt:
Carlisle Power Snowmobile Ultimax XS Drive Belt
Was recommended by a Magazine that puts lots of miles on test sleds. I change mine every 2,000 miles which is considered very good. Shop Amazon or Ebay.
Clutch need to be tuned for your type of riding, snow consditions, your weight and even the elevation. ON a long, hard climb, you want to reach max. RPM, yet not over-rev....Probably between 7,900 and 8,200 RPM for your dragon?
It's worth a few hundred bux to get a local clutch guy to get the correct weights, shims, helix, and springs that are right for you.
I ride with a few turbo guys. They are always either tinkering or being towed out. These engines start out making 165 HP out of .8 liter.......Putting on a turbo to get more is asking for problems.
Most forums are like ghost towns now as everyone is on Facebook.....A good forum where you can ask questions is: (There is a Polaris Turbo sub-forum)
SnoWest Snowmobile Forum