@deep_333, thank you for the suggestions. I've spent the last couple days reading about Rythmik subs. I'm impressed by what I read about both the F12 and the F8, but at 65-75lbs, they may be too heavy for me--but I appreciate the recommendation.
@northman , Even with the Rythmik (technically the fastest subs out there), i wouldn't touch their 12 inch driver F12 or bigger for Magnepans...The FM8 is the sub with the smallest drivers they make.
This is also one of the challenges with MLogan electrostats. Their own bass driver can be perceived to lag a bit for the discerning ear... not a unique problem with Magnepans alone.
You could also try out that KEF KC62. It is a fairly recent technological wonder in the world of subs, if you ask me. A dealer like crutchfield has a 60 day no hassle return policy, if things didn't work out right.