Ken you keep talking about loudness, I'm not!!! Transient peaks in the music and a amp that can handle it with the given speakers at all volume levels. This typically refers to loud musical peaks, such as a drum hit, that are above the average musical level. 1 watt of amplifier power can be loud, but for very dynamic music you must also have the headroom to reproduce the instantaneous blips of loud sound that last for milliseconds or even just one wave cycle.
As far as my MC275 x 2 bridged mono @ 180 WPC, It totally sucks finding speakers that work great with them. In fact after three years I still haven't really found what I like with them. I keep going back to Sansui SP-5000 or SP-5500 @ 90 watts and 125 watts at 102 db respectively as the best. If you notice that combo is over powering the speakers by at least 70+ watts. That said
IMF RSPM Mk. IV, JBL L250, Martin Logan Sequell II, eat the amps alive but are far better speakers. However this list of speakers all sound better with high watt amps that I have paired them with. The Sansui's even sound far better with the 180 watts of tubes than any amp I have driven them with in the sub 100w class.