Tires!! Skid plates, either Richocet (aluminum) or Baltic Iron (high density plastic). Spring spacers for the front shock to eliminate the dive or else purchase better shocks.
Maxxis Bighorns are pretty popular these days. I've had some on my 2004 since 2004 and they're still good today.What kind and brand of tires would be best?
The original Bighorn or 2.0's are good,, your riding terrain will dictate your tires, but if you're riding through any amount of mud the BH's suck, and cleaning the tires off are a PITA.