I know someone using the Icepower IceEdge modules on his Thiel CS3.7's and he can blast it all he wants. I have tested the IceEdge module to do 1000 watts at 2 ohms. That is a lot of power but less than half on what a JC-1 will do.
I think very old design speakers with this kind of impedance don't make sense. You limit yourself to amps and I have no doubt there are far more transparent higher efficiency speakers out there.....Check out Spatial, GR Research, Tekton. These speakers are very sensitive and very transparent. You could even make some speakers for very little that would be mucho better....and easier to drive. Almost everything I have is DIY.
BTW, the Stereophile review shows a 2 ohm load for the CS5....where does one half ohm come from?
https://www.stereophile.com/content/thiel-cs5-loudspeaker-measurements-0