I am probably going to exchange my 16GB Air for a 32GB today at Best Buy and had a few questions about it before I do: 1. Does AppleCare+ simply transfer over to my new device, or will they have to cancel the original one and redo it? 2. Can I pay the remaining difference in price ($120 or so) with cash? 3. Should this whole process be pretty simple and hassle free? Just making sure I have all my ducks in a row before I go over there. Thanks!