The NGK V power are nickel/copper and work the best. But on platinum plugs that car would run consistently poorly, the reving is a separate issue. Did they replace the actual throttle body, or the drive by wire sensor? Really sounds like the DBW has gone nuts. Other possibilities are the MAP sensor and IAC. Has the rubber tube air intake tube from the air filter to the throttle body rotted apart yet? If so replace it. If not, pull it off and clean the MAP sensor with electronics/contact cleaner.