I play streamed music though the spdif input of my Opus via a Squeezebox and it sounds outstanding - as good as the CDP in my opinion. FYI, Resolution Audio makes a "extra sources" unit that connects to the Opus that would allow a direct connection via USB if that was your preference. Perhaps ask Jeff at RA what he suggests.
http://www.resolutionaudio.com/products.html
http://www.resolutionaudio.com/products.html