Efficient, affordable speakers for SETs?

Emerald Physics 3.0s should be awesome, but...
FYI: as to SETs, OCDHiFi Guy (YouTube) is now importing 120w++ SET from Serbia

The Klipsch Reference Premiere line of loudspeakers are an excellent, low cost option.
Pi Speakers offers various high efficiency speaker kits that are also an excellent, low cost option.

I’m using an Audion 300b 8 watt SET with Zu audio Soul Superfly’s and rarely need to turn the volume past 9 o’clock. The Zu’s are very efficient and have great dynamics and imaging. Very happy with this setup. It was quite a big step up from the Decware Torri Jr with Errx speakers I had previously. 

Thanks for the additional recommendations! The Klipschorns are the first high efficiency speaker I ever heard. Klipsch speakers are not my cup of tea. Pretty bright.
A lot of people swear by Zu speakers.
I only heard them once in an Audio industry friend’s house with his super expensive 2A3 amp and like digital front end. I wanted to run out of that room. Hard to imagine a higher end set up or a higher level industry guy. But I don’t want to rule out Zu speakers. It is just that their sound did not sit well. Surprised that no one mentioned Avant-garde. Over my price but the latest ones seem amazing. Even though MP4, the best YouTube I have heard in titled “Garrard 301 vs Studer”. A super system with AG second from the top pushed by a Nagra 300B.
The Charney Voxativ speakers are very interesting. Looks like the cheapest way to get into the fabulous Voxativs!
I have found that dB sensitivities are not nearly as important as the impedance curve. My Tetra 506s are 90dB but only dip down to 6 ohms staying mostly at a flat 8 ohms. And they were designed and voiced with 8 watts of 300B. Mine run very clear and unstressed.
I do imagine that they might put out more sound with more power but at my listening levels I hear a lot of information. Do feel I am hearing the unstressed character of the speakers. And I have realized, more than anything, that the character of the speaker is most vital. Assuming the right amp match, a speaker’s voice must be “digestible and delicious”. Is it perfect, who cares!

I agree with the high efficiency speakers.  I have a custom pair for my family room setup, which are driven by a 45/46 SET amp.  (Both are designed by Don Allen.)

The speakers use Eminence 15" coaxial drivers.