If you're on a $500 budget, your only option is nitrous. Pickup a ZEX kit and spray a 50 shot. It'll more than likely give you 50HP to the wheels, as these cars react awesome to the bottle. Be prepared to start breaking transmission(ie: diff, syncros, clutch) items with that power. I put down 206 to the wheels with my 3L and full bolt-ons and tune, but my tranny isn't stock. Believe me, $500 is NOT going to get you there without the bottle.
Mark