Excellent link, John.

Again, the modeling shows that even with the amplifier of the 'matched' power (speaker 100W, amplifier 100W) the damage from the distorted waveforms is, well, questionable. However, there's a firm belief that even a very low power amplifier can damage a high power speaker if clipped - see the quote from Ian. I think it's way off. Well, I can understand him - they are about to start selling new, 'powerful' amplifiers