I have just setup my DNS-320 and am considering upgrading to the 325 due to having a couple of users utilizing the box and its HP does not seem to be enough. There was a lot of time getting all the data to the NAS and I would really hope not to have to repeat that exercise if I upgrade. Can I just take my 1TB drive out of the 320 and insert into the 325 and it will work or do i have to reformat and start all over? Even though the file formatting should be the same not sure if there are some low level files on the disk that will keep this from being a plug and play.