My father put Supra brakes on his GS300. The rotors weren't balanced correctly. So he started to get a vibration and after 500 miles they were warped. He got new ones for free (the others were under warranty). They said that they had a batch that weren't balanced properly. The new ones have several thousand miles on them and no problems. He got his old ones turned and rebalanced as well. Before he fixed his old ones we compared the two and you could see the difference in the balance. They use weights like they do on tires. I didn't know this either until we ran in to this problem. As for the Ebay thing...I didn't look at it. I would just buy from CPark as I did before.