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? 
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Thanks and shout out to all who took time to read and answer my thread. I appreciate all your responses and am gaining knowledge which I was seeking. Thanks!
Having ordered a Rogue Pharaoh  hybrid Integrated recently, spur of the moment I then realized that I might have a problem. Hence the thread. The Pharaoh is combining a tube Pre with a SS class D amp rated at 185W 8 ohm and 350W 4 ohm, no 2 ohm rating given. I'm really hoping that the 185W will be sufficient to drive the B&Ws at my sometimes listening levels 85 - 95db but sometimes at a little higher at 100db as measured on my Radioshack SPL meter. Never more than 100 (occurs when really partying down hard). Rare occasion indeed!
There’s a Krell KSA 300s up for sale right now that you may want to consider given your listening habit and previous fondness for the brand. You may just need a floor jack if you need to move it around the room.
Is your SPL meter measuring with "C" weighting?

Most quality 4 ohm amps can handle 2 ohm impedance dips. The Rogue will be fine in that regard. From personal experience with that amp, I can tell you that it doesn’t sound anything like a full tube design, even with vintage 12AU7s. It seems many buy these (and the Sphinx) amps thinking they’ll get the best of both worlds: high damping factor and power combined with a lush and 3-dimensional midrange for which tubes are known. I’m sorry to say that is not the case. These hybrids merely sound like other Hypex class D amps. But not only do they not emulate a true tube amp, they don’t possess the impressive bass depth and heft of a good SS design. Compare one, level-matched, at about 70db to any decent class AB amp and you’ll notice a huge disparity in bass extension. However, if driving your speakers to high SPLs without clipping is your goal, they’ll do just fine.

I’ve also had the Rogue Audio Cronus Magnum II. I was surprised by how much it outperforms the hybrids in every respect, partly because a Rogue employee suggested I buy the Pharaoh.

In fact, my performance ranking for their integrateds: Pharaoh < Sphinx V2 < CMII.
Yup, I actually preferred the Sphinx to the Pharaoh. Its soundstage wasn’t as wide but it was better balanced and actually seemed more powerful.

Use the Pharaoh in your system for a while so you can truly appreciate a real tube amp when you finally take the plunge.
I had a Cronus Magnum II with the KT120 tubes.  I changed out the 5 signal tubes but never got it to sound that great.  At 2500, it is a lot power for the money but there was a certain grainey sound I could never warm up to.  I sold it  pretty quickly.