Just a note on the dirty air filter, it probably wasn't hurting mileage (see the bottom of this page
Gas Mileage Tips - Keeping Your Vehicle in Shape ). I probably take it too far, though. I haven't changed my Prius' air filter in the nearly 45k miles I've had it...
Did you remove the dealer frame around the rear plate? I remove all the dealer stuff as soon as I get home, they're not paying me for advertising.