 Started at about 5000 miles. Dealer rotated tires. Still thumping. Dealer said tires were feathered, needs alignment. Brought car in for alignment but was told car needed new front and rear differentials. Differentials installed 2 weeks later. Thumping has been significantly reduced. I asked for alignment to eliminate that as an issue. I was charged $150 for what should have been a warranty repair. I was told car needed new tires at 13,000 miles--typical of run-flats??This problem, coupled with the screeching brake issue previously reported, has made owning this otherwise fine vehicle a headache.Update: Replaced runflats with 4 Continentals standard on Audi’s. Wow! Quieter, smoother riding, 90000 mile warranty. Bought Continental road repair kit instead of spare tire  plus have M-B and AAA road service.  I still think proximity warning system is very bad. Seriously thinking of Audi Q5 soon. Brake squealing backing up is coming back. I would not recommend this car to prospective buyers because of brake noise, run flat tires, and poor proximity warning.