For many years I drove my 2.5's very successfully with a Cary SET 300B amp putting out about 13w max. This combination was recommended by Arnie, the guy who founded Audiogon years ago. It was rumored that Denis Had used Proacs when voicing his amps.
@mozartbrain If you read a lot of review of the 48R carefully, you'll see that they say that the ribbon is well integrated, better than most, but that if you system is already fairly revealing, they may give too much of a good thing. I've tried in vain to find feedback on the D48, with the dome tweeter.