I have a 25 year old Pioneer 185 watt (SX-1280) receiver hooked up to my M80's and I had problems after I hooked up the M80's. The receiver went into protection mode at levels it hadn't with my earlier 8 ohm speakers.
The M80's were not at fault. Becuase of this problem I sought out ALOT of advice and eventually made some basic adjustments to the receiver. (It turns out DC offset and Bias needed adjusted) My initial thought was it had to be the 4 ohm load but they were adamant that was not the case. I'm glad I listened. With things running the right this combo sounds incredible.
