x2 on the no skids. Of course I don't really ride rocky terrain, but no body skid for me and my stocker skid, although badly beaten, works for me. Probably gonna get another stocker cause they have the best ground clearance.
As for cheap mods, remove the airbox lid, take out the drain plug boot. Learn to hydroplane or avoid really deep puddles first. Add exhaust and rejet. Pro Circuits are nice and cheap. Any nice used pipes are good too.
Timing plate +4. This smoothes out your midrange and helps get rid of lag.
Reeds will help out your top end. You can just get the Boyson Power Reed petals and bolt them to your cages. Then cut off the rubber baffles on the cages for better flow.
Get your stock head shaved to make more power. It's the cheapest way and works.
Definately some kind of front aftermarket shocks. I bought my shocks used for 200 bucks. Anything is better then stock. Adjust the rear shock to suit.
TIRES! Raz'r or Holeshot HD's. Definately 6-ply.
PRACTICE, PRACTICE, PRACTICE. There is no better mod then seat time. Become one with the bike. Until it is a living, breathing, ass kicking, extension of yourself.
Good luck.