I see that Amazon has a nice sale on the 2GB Western Digital Caviar Green drives, and I was thinking about switching them out for the two 1TB drives I am currently using in a RAID 1 setup. As I understand it, the drives in a RAID 1 setup are mirrored. So if I want to switch them out, would I switch one of the drives, wait for the two drives to be synched, and then shut down and switch out the second drive? Also, how can I tell when the two drives are synched? Thanks!