@ronkent, I've posted much of this before on this thread, but here it is again:
https://www.stereophile.com/content/thiel-cs24-loudspeaker-measurements
Notice that the Thiel CS 2.4's spend the vast majority of their time "..significantly below 4 Ohms between 100 Hz and 50Khz.." with a challenging phase angle to boot.
https://www.psaudio.com/products/bhk-signature-amplifier/#tab-specs
Notice that PS Audio only indicates that at 2 Ohms the BHK 250 is only "Stable for musical transients". That's a rather low bar for these speakers, basically saying that the amp won't blow up if briefly exposed to 2 Ohm loads. No mention of how much power and for how long it can deliver that power into that load. Well, never mind "...musical transients" we can see from above that the Theil CS 2.4's practically live in that impedance region.
Now the BHK 300 seem to be spec'd much more up to the task, though the amps are not quite doubling down to 2 Ohms. So one is paying for some unused power over the vast majority of the time. Still this would appear to be a pretty good match.
https://www.stereophile.com/content/ps-audio-bhk-signature-300-monoblock-power-amplifier-measurement...
Notice the last sentence: "....,though it will perform best with speakers having and impedance of 4 Ohms and above.-John Atkinson
I have no doubt that these are fine amplifiers, and that they can provide much enjoyment, but at nearly $15K I think one could find amplification better suited to the demands of speakers like the Thiel CS 2.4's
I don't mean to pick on PS audio (FWIW, I'm quite impressed with their digital products, though they are rather expensive), similar results can be found on many of the other highly touted amplifiers.