I'm not sure about the Paradigm 40's but when I went from 140 watts to 300 watts (into 4ohms) with my dynaudio 1.8s, I noticed that I had real bass at lower levels, and didn't need to be cranked as much to get a coherent soundstage. I'd guess around 150 solid state watts (into 8ohms) from a quality amp (no mass market recievers).
