Hi,
I don't know how many folks might be interested, but I recently picked up 2 of the 6TB SEAGATE drives from Newegg. I got a good? deal $20 off of each. I have installed them in my DNS-325 Rev. A 1 with the latest 105 firmware. The drives were recognized and formatted in both JBOD and RAID 0 successfully and seem to be working ok. I copied about 40 GB of video files into both and was able to stream from the 325 without any issues. There was one minor glitch with the media server not working when I reformatted to RAID 0 from JBOD, but a simple reboot fixed that. I did not try using Standard / individual drives nor RAID 1 and don't plan to. I am satisfied that they are compatible enough for my purposes. You get a total available space of 10,998.57 GB IN JBOD and a hair less in RAID 0. It did offer to give me a 2GB JBOD partition in addition with the RAID 0 for some reason.
UPDATE: Reformatted to RAID 1 and tested by streaming videos same successful results as with JBOD and RAID 0. Oh yes, you get a hair under 5,500 GB of space.