Once again @soix +1
I am powering my Sonus Faber Amati Traditional with an Audio Research Reference 160s in triode mode… so 70wpc and can play them louder, many times the volume I would ever want listen to without loss of dynamics. If tubed amp… then I would not worry much about the wpc, unless very low.
A word about Luxman. If you are looking for natural / musical, this may not be the brand for you. They have great specs for power but have a very limited midrange and very poor rhythm and pace. Listen to the brand for sure, many people love them, but make sure you feel it is complementary to your system. To me McIntosh is in one end with accentuated bass and midrange and a real lack of detail and Luxman is on the other end with accentuated treble and bass, lacking in musicality and midrange bloom. You are right, best way is to try this stuff in your system.