Best Mods for a Mac-mini used as a Music Server

Mac mini costs about the same as microRendu. A good expendable NAS will cost $400-600. Drives like Western digital Red will be cheaper than external drives that attach directly to a Mac. You won't need as expensive cabling. A linear power supply is recommended in either case.
All in, to get a far superior set up it might cost a bit more, but we are talking $1k additional or less, not $10k+. 
Food for thought if you want to test the deeper waters. 
With the Mac, try Audirvana+ software, best soundwise of many I tried. Cheers,
Spencer 

@sbank 

Thanks so much for your thoughtful responses.  I will definitely take your wisdom into consideration.  I have "seen" a microRendo in my ruminations & googling...I will do some deeper reading.

Dave,  I'm sure by now you're up and running with your Mac Mini, but I wanted to pass along that I have been extremely happy with my Mac Mini that I had modified by Benjamin Zwickel at Mojo Audio.  I purchased a Mojo Audio Watt, external linear power supply, and a Mojo Mystique v2 NOS DAC.  My music is stored on a Synology NAS and I play it through JRiver's Media Center.  As I said, I have been totally pleased with the set-up.

https://www.mojo-audio.com/mac-mini-upgrades/

I run Roon on a Mac Mini.  Today I added a microRendu with CI power supply.  It takes ethernet and outputs USB to an Ayre Codex connected to an Ayre A7e amp that drives a pair of KEF LS50s.  The sound quality is excellent.  Total cost of microRendu and power supply was under $1K.

I bought the Ayre components used, so the total cost of the setup was under $5K, leading me to wonder why I spent so much more on my primary setup.