I used to have a pair of the original Concerto Grand Piano's and drove them very nicely in a medium sized room with a 70 watt per channel c-j Premier 11a. When I switched amps to an Air Tight ATM-1 with 30 watts per channel I found them to be too tough a load for that amp. Almost, but not quite. I would get some soft clipping in the sense of compression during loud passages or bass heavy music. I then switched speakers to Alon Lotus's, problem solved. Based on that I would imagine at least 50 tube watts if not 70. That would be a minimum, but the more the better, Sonus Fabers are known for being a bit power hungry. Good luck.
