So you really want the Mac Mini to have fast I/O? That would be the OWC Mercury Helios with the OWC Mercury Accelsior PCIe SSD installed.
I was curious if the Helios + Accelsior combination could beat the internal OWC 6G SSD, and indeed it can and by a massive amount! So I connected the Helios to the MacMini, and then connected my NEC PA271W wide-gamut display to the Thunderbolt pass-thru port on the back of the Helios— works great.
Observe that the Helios + Accelsior PCIe SSD drops the time from 30.2 seconds down to 23.0 seconds. WOW!