The M80v2 were the same, dull presentation. I don't know about v3. v4 are all a completely different emotional impact. I'm considering trading in my 500s for 600s.

It's great that you are satisfied. I suggest adding one more 600 and arranging them opposite each other. For example, one in right front corner and the other in rear left corner. This did wonders in my living room with dual EP125s.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated