I do not own an Integra that you have so I have no real experience.
I have owned a Harmon that I managed to blow the power supply up on while under warranty but that was from a different cause.
The receiver has only so much power. Ohms law says that V=I*R. In the receiver, the voltage that it has coming in is for the most part a constant. So the only other two variables is the current (i) and the speaker resistance (r).
Some may say that the speakers resistance is a constant, but look at the chart for the M80 speaker and you will see that depending on what frequency it is producing, it spends a lot of time below the 6ohm mark.
So as your resistance gets lower the amount of current goes up to balance the equation for your constant voltage. Inside your receiver the more current that is going through the circuits generates HEAT. As your receiver starts to get hotter, the components inside will start to fail.
Now there is the second component inside your receiver that has an effect on this heat. The volume knob controls how much of that potential current goes through the amplifier that is the biggest heat generating part of your system. The lower the volume, then the less current.
This is all overly simplified but it illustrates the point. The M80's can be played on your receiver, with a large *
If you do play too loud, you will cook the receiver and shorten it's life. The loudness is an additive thing, so playing at -30db for a whole day might be just as bad for the receiver as playing at -15db for an hour.
Just make sure that you give your receiver adequate ventilation.