Alas, after much, much consideration, just today I decided to purchase another brand of monitor speaker.
In the end, I concluded that my amp (~100 WRMS/channel into 8 Ohms), simply is not powerful enough for the occasions I would want to play the SCM19's at high volume, and I really don't want to replace my amp (Spectral DMA-90, which I think is very special) at this time. Also, as I mentioned somewhere here before, the SCM19's to me don't sound particularly compelling at low volume, and I do much of my careful listening at night when my children are asleep.
Ah, but, the SCM19's sound amazing (to me) in my system at moderate volume, and if my listening space could be closed off from the rest of my house, I believe I would have purchased them (or the SCM20SL's).
Thanks, Loftarasa, for sharing your experience with your SCM20SL's. Let's see: In about eight years my youngest kids will be off to college. Maybe at that time I'll be ready to revisit the SCM19/20SL's!