I am thinking of buying a Time Capsule with a small hard drive and upgrading the drive to something larger. There is ample documentation on the web as to how to do it, but I am having a hard time finding any details as to what the upper limits of drive size are. It's especially confusing since there are four generations of Time Capsule, and each one may have a different upper limit. So, what is the upper limit of each? And, if you only know the answer to one specific one, that would be great, too.