Just to add my experience to this conversation.
I have the Walsh 5's series 2 and drive them with a Carver amp. that outputs 600 watts per. ch. into 8 ohms and 1200 into 4 ohms. I have on occasion play them loud enough (in a 16' X 24' X 9' room) that i cannot hear my own voice when taking normally. I heard that the series 3 are easier to drive but don't know if that is a fact or not.
I have the Walsh 5's series 2 and drive them with a Carver amp. that outputs 600 watts per. ch. into 8 ohms and 1200 into 4 ohms. I have on occasion play them loud enough (in a 16' X 24' X 9' room) that i cannot hear my own voice when taking normally. I heard that the series 3 are easier to drive but don't know if that is a fact or not.