Your speakers are a very hard load for an amp, looking at the Stereophile tests. They need an amp that can give high current into 2ohm loads, it would be better to find an amp that can almost quadruple it's 8ohm wattage when it's driving 2ohms.
Neither of the two amps you mention seem to able to do this,they will work, but there maybe better out there, that can come closer to quadrupling into 2ohms.
http://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements
https://www.audiofreaks.co.uk/images/np_KA_S_600_LoRes.pdf
http://www.stereophile.com/content/asr-emitter-ii-exclusive-integrated-amplifier-measurements
Cheers George