Well.. in another twist. My listening test between DACs was very compromised I just found out.
Kind of ashamed about it, but only fair to post it here.
I still had Sonarworks Reference 4 running as an ASIO plugin in Foobar2000. Still had it in the chain, bypassed of course, because I had just been testing some EQ on my headphones (don't like the Reference curve but it was one of the things I was comparing with). And I had an upsampler to 176.4 KHz running as I reported. I was just listening to some music and I don't remember why but just changed the order of the resamper to come after Reference 4 instead of before it as before. And it changed the sound!! Immediately removed Reference 4 completely from Foobar2000. And boy, what a great sound! I had just moved my nearfields 2 days ago to a temp position on small stands on my desk (long story) and when testing DACs I already though hmm this doesn't sound that great thinking it was due to the position of my nearfields. Was I stupid, it was Reference 4 in bypass mode messing up my sound (no I'm not talking about the lower level from Reference 4 in bypass mode, but sound quality being totally degraded).
I don't know yet if this is something Foobar2000 specific in combination with Reference 4 as an ASIO plugin, or 176.4 KHz specific for Reference 4 in general.
Anyhow, too bad I can't test against the M8A v3 anymore. Perhaps I was not all wrong with my earlier impressions that the difference is quite large between it and the D2, an opinion I formed on my main speakers but in less carefull A/B, but without Reference in the chain.
In any case, I did hear a subtle difference even with Reference bypassed but in the chain, but both DACs were at that point outputting pretty much garbage..
Again, ashamed I didn't notice just how bad it was right away and thought it was something else..
But very happy I now have absolutely fantastic sound on my nearfields as well!
I may test Reference bypassed in a DAW later on with different sample rates to see if the huge bug is there as well, though I may not as there is currently no software around I hate more..