My understanding of the "New England sound" is that it's a combination of sound, speaker type, and location/maker.
Obviously, they'd typically be made in the northeast, but sort of grew out of the Boston area, and specifically the Kloss/Villchur/Allison relationships. Ed Villchur and Henry Kloss founded Acoustic Research, Kloss left to start KLH and then Advent (and I think BA, Cambridge Soundworks...), Roy Allison came in to replace Kloss as VP. Allison later went on to make great speakers on his own as well.
Villchur came up with the concept and patent for the acoustic suspension ("sealed box") speaker. Kloss designed the original AR woofer. The system really was a change from the open box baffle with a hole that had been the norm, and was much less efficient (that is not necessarily a bad thing, but also really was the catalyst for the reciever "power wars"), but had a reputation for producing a much more realistic and lifelike sound. AR was famous for live vs. recorded tests.
The sound. To me, it's the 2-way acoustic suspension that is the essence of the New England sound, but obviously more complicated speakers were part of the scene (AR-3, etc). Maybe the 2-way is just the Kloss sound - probably my preference anyway. The reputation is for very tight, controlled bass, a slightly rolled off high end, and sort of a "musical" feel. Pretty much the opposite of horns.
There's lots of info on these speakers and companies at classicspeakerpages.net. But others that are smarter (which is just about everyone here) please feel free to disagree with or correct me on any point.
Not sure about power handling. That's always been sort of a recent meaningless marketing ploy to me. I could be completely wrong, but it sounds like you're clipping your amp rather than the speakers not being able to handle a certain amount of power.
-- i.e., those unwilling to plunk down $10 for a subscription to their rag -- on their website.
