When streaming audio files, connecting a computer directly to one of the pre/pro's HDMI inputs (i.e. using an HTPC) is one way you can (eventually) guarantee that the correct audio is being sent to the pre/pro. DLNA servers and clients each have their own unique limitations in what formats they can transmit or decode. There also are many settings in the computer that you have to configure correctly in order to ensure that the audio isn't being modified in ways you don't want before the pre/pro gets it.
(Personally, I use a laptop with a media player which supports WASAPI. See www.avsforum.com/t/1495316/which-media-players-reconfigure-hdmi-to-match-number-of-source-channels)
My idea is to keep a NAS in adjacent room due to fan noise etc (although a small NAS should be quiet).
The NAS would plug directly into the wireless router and then a Ethernet cable thru drywall to plug directly into back of 80.3 (if wireless streaming doesnt work)