The level would depend on how loud of an average level that you use and how wide the dynamic level of the material being played is. Typically, a loud average level which wouldn't cause permanent hearing damage would be 80-85dB, which would use 1 watt or less with the M80s. Allowing for some classical and other material which has a very wide dynamic range, 20dB above the average level, i.e., 100-105dB, might occasionally be hit briefly, but would require less than 100 watts, even for the peak.

-----------------------------------

Enjoy the music, not the equipment.