I confirmed with tech support that, although you MIGHT be able to make it work (no confirmation), a DX120 KSU2 is not supported by Vertical to go on the DX80 expansion. The person I spoke with had also heard that they were in pretty short supply from the various supply sources. He also understood how it was pretty poor to have to go back to a customer whom you told bought a system that supported 16x48x8 that they now had to do a forklift change out in order to support the expansion to get to the promised capacity of 16x48x8. Taking away a touted (marketed by the manufacturer) migration/growth path is just not right!