Have a chat with the guys at the boutique (Clemenceau Rd?). I would try the MS600 with and without your DAC. You may be pleased if the MS600 performs well. It will significantly improve the SQ of the C15 as essentially the C15 just serves the music.

If you really feel the DAC adds benefits then try also the MS200 as a cheaper network source. These work very well too.

Home demo is what you need.

Let us know how it goes.

Rgds,
Nick