I ended up unstuffing the speakers in my main room. It just didn't sound natural. I continue to be very happy with wide open sphincters.

The living room is another story. I'm finally enjoying tunes in there now with all holes stuffed.

Eventually the M3s may get replaced with M5s which are most definitely better if the M100s turn out to sound better in my main room.

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