I am currently taking an introductory course into principles of electronics and speaker ohms has me a little confused.
I have learned from class that the greater the ohm rating, the greater the resistance. So it seems a little counter intuitive to me that the M80s, with 4 ohms, would be harder to drive than say an M60 with an 8 ohm rating. I tried to ask my instructor about it and he really did not have an answer to that, either.
Yeah, your way of thinking is correct as the advantage of a 4ohm rated speaker would be that it presents less resistance to the current flow which will allow the speaker to pull more power from the amp/receiver. However, because of this the amplifier must be designed to handle this greater flow of current. Therefore, with low impedance speakers (impedance varies and it is the dips/phase angle interaction to worry about) can sometimes cause the amplifier or receiver to overheat and/or go into current limiting when pushed hard. In either case will cause the electronics to shutdown or in the worst possible case, permanent damage.