Heard the Dunlavy SC-IV/A's bi-amped with (2) Classe CA-150's. The sound was awesome (deep tightly controlled base, wide open soundstage, that sense of the music being there rather than coming out of (2) speakers). Classe makes larger amps, but you don't need any more power (or expense I would guess). I would definitely recommend bi-amping rather than (1) amp like a CA-300 with the equivalent power. It is an excellent amp too, but bi-amping works better.
