Dump the Renthals; replace with TAG tapered bars (no cross bar). Add some Applied triple clamps (upper and lower), and get some Summers Racing handguard mounts that bolt to the triple clamps. While you're at it, get an Excel/Talon wheel set with the gold wheels and hubs, because they're shiny and cool. This will only set you back a couple thousand, which should leave room for a W.E.R. shock bladder, some EBC brake rotors to replace those weak stock rotors, and some eRider billet aluminum levers.
Enjoy!