You don't say why you need to replace the Mini. If you are happy with the current setup, then replace it with exactly what you now have. Used Minis are plentiful and relatively cheap. You could even swap the hard drives between the old and new to avoid any changes in configuration.
Replacing a MAC Mini with new one...
I have been using a MAC Mini dedicated to my audio system. I run it into a Bryston DAC-1 via the Audiophilleo 2 with Pure Power. I am happy with this setup however need to replace the MAC Mini. I am looking for advice on which Mini to purchase and on how I should have it configured. Thanks in advance.