I have successfully installed Spotify Connect on my PI 3 with IQAudIOs PI-DAC+ and the latest version of Runeaudio. Running excellent with the built in WiFi.
I have used this guide for Volumio (using google translate):
http://powerpi.de/spotify-connect-auf-d ... bedienung/
I love the result and it sounds fantastic. But I can't get it to auto start as Volumio is using another OS. I need to make this line to run on startup:
/root/spotify-connect-web.sh --name Volumio --username xyz --password 123456 --bitrate 320