Remove ALL shims, Use your same belt and it will be like a new ATV! My belt would squeal like a pig until I followed NYROC's instructions from his website. Now it has NO squeal. Like NYROC says, If you can change brakes on a car you can do it yourself, But you will need to make you a spring compression tool. Instructions for this tool is on his website too.

 

I just put a new belt on, not that I needed it badly (2400 miles on the first one), My bike came with two shims. I had removed both of the them by 800 miles. Now with the new belt I'm running 1 shim. You can here is if running in gear, but just sometimes. That tells me I'm tight enough. Besides now that I have shimed it a few times I can take the last shim out in about 30 minutes, no big deal. I'll run it with one shim for about 500 miles and then remove it again. If you keep that belt tight it will last a good long time. I could probably get another 500 miles out of the old belt.
My new worry are the other parts that might need replacing in the clutches. Never had a auto before. I'm sure it will need some work soon.