calling all Guru;s, Ideas on audiophyle high effeiciency speakers solicited

Wanting to enter the "Tube system" realm. After extensive research I've come to realize that my current low efficiency speakers B&W 803D2 require a lot of power and may not cut the mustard using tube gear. Although I truly love the speakers I may end up swapping them out in the future to accommodate my new found rabbit hole. Tube amps in general provide only minimal power certainly not enough for my listening habits. 
Anyway what , by any standard, constitutes a high efficiency speaker? is it a rating of 80....... 90, 92,......97? just what is it. Do speaker manufacturers fudge the number on occasions? How do we know? Is a 2 way design inherently more efficient than a 3 way? Does  the amount of speakers in a cabinet affect efficiency?
Last of all what are some audiophile grade speakers?