Cool review -- although I am sorry about the bad vibes between the principals here and at GR (which I realize are fairly asymmetric vibes, at that).
FWIW, I've fiddled with single-driver loudspeakers since... well, technically, since birth, since I grew up (literally) listening to Electrovoice twincones (like these).
(EV "Wolverine" LS-12 'fullrange' 12" drivers)
Well, I have to say that this tests like a "full-ranger" with come care and thought put into pulling it together -- in the best and worst possible senses of that notion.
Heck, maybe I
should box up one of these and send it out to Washington for a spin.
I like these -- although I actually liked the sound of these little drivers, the infamous PartsExpress p/n 269-469
69 cent wonders (Pioneer OEM, but once sold under the "Onkyo" brand by Madisound, too), even better in big vented boxes (repurposed Brand X monkey coffins, randomly chosen and using the tweeter cutout as the "port"!). But that's another story entirely.
(EDIT: Full disclosure, a 4" driver)
Great review and, still, a great topic!