I did end up getting the extra 2 gig ram upgrade. I didn't end up getting enterprise disks (out of my price range) but I did get the new WD 3TB Red drives. I think they should do nicely. I got 6 of those. Unfortunately whilst I do have my NAS, my drives are still shipping....
I was running 8 x 2TB drives under SHR2 which gave me a total of 10.72TB and I had 1TB free and wanted more. So I started the upgrade as follows: REPLACING DRIVES Power off, remove 1 x 2TB drive. Power on and the DS alerts that the volume is degraded and I need to repair. ...