So I had my rear changed early on when I bought the car new. I had read that lot's of people were having issues with the lash setup. It has been running fine ever sense but then I started to develop a vibration. I'm now at 58,000 miles.
It seemed to come from the drivers front wheel so I put the car on my lift and first spun the tires with my hand and listened for any noise or difference with each side (Driver, Passenger) Then I looked at the sides of the tires (straight on) as I spun them to see if I had any wobble. Next I switched the tires Right and left and drove the car. As I did this I checked the rotors and brakes. Still had the vibration at low speed. No change when I put the brake on. So I switched the tires back. I also pushed up on the carrier bearing to see if I had movement (none).
So now I'm thinking Wheel bearing and brought it to the dealer.
They drove it and felt a slight vibration and when they put it on the lift under load they said they could hear the rear. He checked the part number for what they replaced the last time and what it calls for now. The part numbers are different. He said that they replaced the original rear with the same part that has now developed an issue. It's all under warrantee so they are replacing the rear again with the a new one.