As for the EnABLed drivers, they just sound more focused over the entire spectrum and IMO, the driver has much less of a tendancy to shout at you, but it loses much of that in the break-in process. I've had several different drivers treated and they have all pretty much responded the same in terms of sound improvements.
As for the rear chamber, several folks have tried filling it and everybody says that it was pretty much a total bust and that it did nothing -- good or bad.
Out of all the tweaks, I'm sticking with the BBs or shot as the most cost effective and most clearly audible.
-- Jim
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)