Make sure they use the finger plate adapter. Discount tire does not believe it needs to be used on factory wheels. However, it does, according to Toyota Service bulletin SU002-96. A finger plate adapter is also called a Haweka Adapter. Once I asked Discount Tire to use the adapter on my 3rd gen the steering wheel shake went away.
HAWEKA
Of course the vibration could come from several causes, this is what worked for me.