That's an extremely diverse and worthy short list of speakers, mca!
The Eminent Technology LFT-8 is probably about as inefficient as the CS2 is efficient.
An earlier ET owned by a friend - maybe the LFT4 - was about the least efficient speaker I have ever witnessed, swallowing up the output from a 150 W class A amp and producing shockingly little acoustic output to show for it.
maybe you should go for the TRW-17 sub by Eminent Technologies:
http://www.eminent-tech.com/main.htmlI scanned the review by Peter Moncrieff (under "Latest News" on the TRW-17 page) - twelve pages of intense exploration into the value of sub-20Hz response. Really made me want to hear what he was talking about
I especially liked his description of the comparison between otherwise top-rated subs - flat to 16 Hz and the TRW-17 when playing the apparently well recorded cannons in Master and Commander. This was on page 152, near the top (ten pages in).
I know if I had 25 large to throw away, I would be calling Bruce Thigpen of ET!