Suggestions for high efficiency speakers?

A) Klipsch is on my list to listen, especially as the Forte IVs were cited in the Stereophile Prduct of the Year article. BTW, my room is essentailly a 280" square with an ell to my right rear into another room of about the same dimensions.

B) I have to try Tannoy, why is so little written about them?

C) Budget? Say <= $15K.

Curious to know what you don't (or no longer) like about your JA RM 25 Sigs. Granted they are probably not the most efficient speakers but they are nice sounding speakers.

I'm with charles1dad--it is the combination of higher efficiency speakers and low-powered amps that is important to that kind of sound.  Most of the better high efficiency speakers suitable for low-powered amps are not budget items unless someone buys used, or builds their own.  There are some not so efficient speakers that present an easy load so they are suitable too, albeit, not playing at ear-splitting levels.  

As the OP noted, Audio Note and DeVore speakers are quite good with low-powered amps, and they are not that extremely efficient.  Klipsch Cornwalls are another candidate.  My current favorite brand for high efficiency are the speakers from Charney Audio.  I heard an expensive, but terrific speaker from Cube Audio (Nenuphar Basis) that is also a good candidate.  

Horning Aristotle Ellipse PM65 speakers are just wonderful and have that immediacy you are looking for. The model under the Aristotle, the Zeus, also delivers what you are looking for. Well worth a listen!

Stanley, the RM25 Josephs are one of the outstanding bargains in audio and I've had them for maybe 18 years. What I'm looking for is that palpability of the notes that really high efficiency speakers do better than the 25s. They aren't really hE but my 20W amp has no trouble pushing them.