Twl, my speakers are quite inefficient and the more the power the better they sing. My amp is rated at 600 wpc into 4 ohm loads. Not the most powerful, but certainly not the weakest. I purchased the speakers before the amp.
My previous amp was a nice amp in so many ways and rated at 195 wpc into 8 ohms. But I could tell that the lower regions seemed to be compressing a little at about 1/3rd full volume.
I believe the system will sound better at low volumes if the amp is designed well, has the power reserves, and if the AC electrical has been configured so as not to choke the AC power needed for the amp during dynamic swings i.e. a dedicated circuit/line.
I rarely play my system loud. But its nice to listen knowing that the system has the necessary elements to play at any volume without fear of strain, congestion, compression, etc..