It was actually Loretta, in an email, that told me:
"You may want to discard half of the stuffing behind the polydome and fluff-up the balance."
When I asked about that, she wrote:
"After extended listening you’ll find the following improvement:
When a passage of music gets loud, they will remain as clear, as at lower volume.
If one chooses to play music very loud, they will not suffer from the mild doppler distortion, from the previous “floppy” dome (mostly center area), not following voice coil movement.
Also, the hard, reflective face of the magnet, now has four strips of damping material (unevenly applied) and cavity behind the dome is stuffed. This has to make a difference, even without the superior dome."
I'm guessing it's a balance between the cabinet stuffing and the fill that was added behind the dome.