So does the warranty coverage start when you buy the car? Are they going to add 14k miles to the end of the coverage? My guess is that you will have 4 years but only 36k miles left. It's not really a fair way of looking at it but what would a used 2011 528 with 14k miles on it be worth on Edmunds or KBB? That is the number I would start from and gradually work up.
You can guarantee those were a tough 14k miles for sure. I think I would pass unless the dealer becomes motivated to sell.