I own the 40.3XD, and it is my final speaker.
Was running with my Jeff Roland Concentra 2, and it sounded wonderful. Had the amp for 18 years and got the bug to replace.
Now using Hegel h590 and am very happy. Using the Hegel onboard DAC for streaming and really do love the set up.
'Still however have the bug to experiment with a lower powered tube amp just for kicks but not yet. Perhaps an inexpensive Raven just to try one day. But for now the Hegel is brilliant.