If you want more power you should start with a pipe and a jet kit. Also replace the stock air filter. If you still want more power mabye a big bore kit if you want ALLOT more power.

Mabye you could change the compression ratio. If you ride allot of mud then a clutch kit might do good but it wont give you anymore power. It'll just get the bike moving quicker. Thats about all I can tell you. Those improvements or trade it in on a grizz.