As Tom said; ..."Consult Stereophile's review for details and considerations."...
Thiel CS1.6 loudspeaker Measurements | Stereophile.com
The high sensitivity might be misleading considering the below 4 Ohm impedance, and the somewhat recactive load.
The NAD C375 BEEis is spec'd as >150 Watts 8 and 4 Ohms. As is is not spec'd to increase steady power with impedance drop suggests current limiting. It does suggest good dynamic power down to 2 Ohms, But as seen in the link above the CS 1.6's are below 4 Ohms a good deal of the time. I think the steady state power output into impedance is more relevant.
User manual NAD C 375BEE (English - 18 pages)
As 3 Ohm ratings are not typical (only the stereo version of the Benchmark jumps to mind), I think it prudent to consider the more typical 2 Ohm ratings when they can be found. A minimum of 200 Watts into 2 Ohms should be considered, and personally would use at least twice that. As @duramax747 wisely suggests YMMV.