Re: Drive belts
I've had great luck with a dayco ultimax 2. After close to 3000 miles on an XLT, I saw about 1/16" difference in width compared to a new belt, and it never hourglassed, a problem I've had over and over with the polaris belts. Now I'm trying a gates xtreme, of which I've heard good things.
As for speed, a belt that fits incorrectly will affect it. Too tight, and it won't shift all the way out on the primary clutch. Too loose, and it won't shift out all the way in on the secondary. The correct fit will also improve your takeoff by ensuring that you start off in the proper "gear".