Dealership wasn't able to take the car out above 60pmh because of the holiday traffic around and bad rain, so no answer yet.

Another thing I noticed, when I took the tires off to put the winter tires on, is that the inside shoulder of the front tire was worn significantly more than the outside shoulder. I had an alignment about a year ago, but looks like I've got some camber misalignment in the front now. Not sure if that could possibly contribute to the steering wheel shake.