In that post you linked, you said:

"OK, that was interesting. No more testing different configurations yet, but played another few CDs while working. On Sheep from Pink Floyd's "Animals" I realized what was different with the sound...

Sheep opens with electric piano and sheep noises, followed almost immediately by bass guitar. The bass is sharply located in the center, while the electric piano has always sounded "out of phase" and smeared across the soundstage with most of the sound seeming to come from a bit outside the speakers.

With the new setup the electric piano was sharply located "over there", off to the right somewhere between 30 and 40 degrees, almost twice as far from the center in terms of angle as the right channel speaker. "

I've been making similar observations with the v4. I am still working on a final verdict between the M3v4 and the M5HP as far as soundstage is concerned.