You might have seen my other post over at the PC Forum, but in case you haven't: it might be worth connecting with member Elberoth over at computer audiophile.com for his view. His reference is a DCS Scarlatti, and he also has a Metrum Octave which he tried with both the OR5 and AP2 with Pure Power. He also tried an M2Tech full Evo stack.
Cheers
Cheers