Welcome to the site. They come w/ alot of robbed power out of the box due to epa reg's. The first thing to do is let it breath. Get a slip on or full exaust, take the air lid off or drill holes in it and go w/ a k&n or uni filter. Jet the carb-main and pilot to the pipe spec's and put a big gun cdi or like brand on it. For about 400-500 you will wake up your quad big time. It wont matter if it seems to be running hot or not. Mine allways gets hot and never losses power. There is alot more you can do, but this will get you started. My quad felt like a week machine until I did the mods. Now I love it.
My tire diameter is 1 inch taller, and two inches wider over the stock size. Its not much more but it does give me more rear skid clearence. They bite so much better then the stock tires did also. I no longer get stuck in minor mud like it did before. It gave me a little more top end speed as well. Here is a pic so you can see what im talking about. I can get you the tire size if your interested.
