Did you use hub-centric ring in the center of the wheels? It is a ring about the size of an average onion ring that fits in the wheels to make them fit more snug on the hub. I'm sure someone can explain their purpose better than I can, but I know they helpe reduce vibrations.
Did they balance the wheels with stick on weights? On the inside of the wheel? There is always a possibility they weren't balanced correctly, but my guess is the hub-centic rings will fix it.
Good luck!
