Alex, you have a name for yourself modding transports like the Esoteric. What would be needed to bring it up to snuff, and similarly, would could or should Matt do to bring his Mini up to snuff?
Agear, those are tricky questions, especially not knowing the audio system synergy in question.
From experience with older Esoteric units, there are some clocking upgrades needed, as well as digital signal path and digital output circuit redesigns. Power supply upgrades might be helpful too.
The MacMini (especially the later ones) are not very desirable for audio server, at least from what I know. The early examples with Core 2 Duo processor had a dedicated graphics card, while the new ones feature the Intel graphics built into the processor. I have experimented and, in my opinion, when the graphics module inside the processor is used, it takes from the memory and contaminates it (because it uses/shares the same memory controller). Best to me will be an Intel quad-core processor without built-in graphics, and that is what I have as a reference in my audio system.
Also, a MacMini, even with a linear power supply is a very similar solution to a MacBook Pro. Some actually may prefer the latter as it runs on a battery power. However, in both cases the multiple charge pumps (switching power supplies) on the mother board supplying everything remain intact, resulting in somewhat mechanical and lean audio quality, at least to my ears. I personally prefer linear power supplies.
Hope this explains it.
Best,
Alex Peychev
APL Hi-Fi