What advice should I know about to swap out my sister's <30 days old 2011 21in iMac (500gb hdd/4bg ram + $100 4gb ram upgrade=8gb ram) for the newly announced 2012 21in iMac? I've never done one of these exchanges before, and want to know if there are any tips that might help. Will there be any odd policies or issues that we might face? Since the new computer comes with 8gb ram as standard, how might I convince them to also honor the extra $100 ram upgrade on the previous computer (which was paid for on top of the standard configuration. I don't want her to lose that $100 dollars while exchanging one base configuration for the newer base configuration. I want her to have the value of the new base configuration + $100, so she doesn't lose any money on the deal. Please let me know what I might expect, and how to approach the situation. Thanks.