I've seen a lot of people asking what the max hard drive size that can be put into the Promise2 units. I successfully replaced all the drives in my R8 and R6 with 18TB drives. Disk model specifics below if anyone is interested:
WD Ultrastar DC HC550 WUH721818ALE6L4 0F38459 18TB drives
The wizard would not complete the setup in the Promise Utility, but manual configuration worked just fine. I spent the last 3 days copying data off of older units to the newly upgraded units, zero issues.