Sorry Craig, just re-read your post. That makes sense, but our ears often don't make "sense" which was one of the reasons for considering a "proper" streamer. If I think about it, I can hear the difference fairly easily between spotify premium tracks and the CD versions played through J River, so something is right about the system, though this depends entirely upon the definition of a *good* system.
Re Dacmagic +: It's possibly not the smoothest sounding DAC I have heard - though that is only the Peach, and the QBD, and of course the original DACmagic over which is it noticeably better, though this could be the change from optical to USB connection. The DM+ sounds better to me via USB than optical (similar to spotify -> CDA)
I suspect it is responsible for the slight shoutiness, which I cannot eliminate by changing the filter settings which have a very small effect, you have really got to be listening closely to detect any difference. Then again the M2 is a bit of a wayward thing, so putting the two together is probably not an ideal match. To put into context though, it's a fantastic piece of kit for the price, with the D18s I em getting close to that wonderful "shimmer" of a crash cymbal. They really are fabulous, I can understand why so many rave reviews about them.