Cube Audio Nenuphar Single Driver Speaker (10 inch) TQWT Enclosure

The BHK 250 has >150 DF, where as the mono block BHK 300 is >350.

@david_ten 

did you move away from the Tekton and T+A system?

The Klipsch is a high sensitivity speaker yet may possibly  benefit from more power due to crossover design and big woofer control. The crossoverless,   very easy to drive load Nenuphar is a different animal. S.I.T. 3 amplifier and Nenuphar is considered to be a splendid pairing. As they say, "horses for coures".
Charles

Since we’re talking about first watt amplifiers that may provide a good match, I’d just like to mention that the F4 doesn’t get enough attention.

25 watts, zero negative feedback, and no gain stage to modify the sound of your source and preamp, all it does is provide current. A very simple circuit. If you’ve got quality upstream components and enough voltage from your pre/source, it is just fabulous. On my Coincident PREs, it beat a diy sit3, pass labs xa25, atma-sphere m60s, a lyngdorf tdai-3400, and Coincident Frankenstein 300b monos.

In regard to this discussion, it has an output impedance of .2 and a damping factor of 40.

And @khragon, I suspect you’ll still love the speakers with your current amps, even if they’re not the ultimate match. If you happen to be in Colorado, I'd happily bring over the f4 & sit3 for a comparison.

cal,
I suspect that the F4s would quite likely work out well with the Nenuphar. I'm somewhat surprised you preferred them over the Atma-sphere M60s and the Pass Labs XA 25 with your speakers.  I get that the Frankenstein's 8 watts isn't enough for your PRE. The Frankenstein would very likely be an excellent match with the Nenuphar. 
Charles