Hi Arktikos,
Long before I had efficient speakers I built a ZKIT1, and even another ZKIT1 and ran them as monoblocks. I loved their sound and their ability to pull more music out of any amplifier I'd heard- but I didn't have the right speakers for them.
Not to be deterred, I bought a Torii MKIV. It was decadent, It is decadent. It is an incredible amplifier and I love it to death. So much so that I started searching more and more efficient speakers and JBL certainly fits that bill.
To cut to the chase, I have a pair of JBL L36 speakers that I have done the entire Troels Gravesen crossover rework to. They sound impeccable with my ZKit1's. I also have a pair of JBL Sovereigns that have had the crossovers completely redone and they are breathtaking with the Torii.
I am not going to lie to you. I will still gladly forgo heightened volume and (what I call) perceived dynamics of multi driver speaker systems for the delicacy of point source/single driver speakers. (caveat being a helper tweeter if needed)
The right chain of equipment- following the correct source (usually vinyl in my case)- feeding the right (wideband) driver seems to surpass every other equation. At least for me.
Please don't be afraid of jumping into a ZKIT feet first. It is a lovely path to splendor

Dam