Ahh, ok now I get it, thanks for the idea Saudor.
But.... the drive is an old style SATA and won't fit in the Mac mini.
Do you know If I would be able to install /upgrade the OS via firewire?
Also I think it now has to be done via the Apple store /internet, so not sure if at all possible and it might turn out that the Mac Pro wont boot from the Mac Mini / Mavericks install.
I will do some research, but if you already know how, then you could save me some time
