T, sure it isn't as good for your amp as if it was just running warm. But with those speakers, playing that sort of program material and at those levels, apparently that's the way it's going to be. Keep in mind that from the numbers you give those speakers are drawing about five times as much power for a given sound level as, for example, the M80s, which are a relatively easy 4ohm load because of their higher sensitivity and flat impedance curve. So, it may not be good for the long term, but enjoy the moment.
