Dal at vandevere oldsmobile in akron ohio or Jason cromer at samtaylorbuick in pensacola florida has teh best deals on optis..

200 bucks for a vented.. think 280 or something for nonvented

Try hooking up a fuel pressure gauge, tape it to your windshield and haul ass through RPMS to see if fuel pressure drops.
Try using some engine restore or sea foam to clean out the engine.