First, how big is your room.

Mine is 12'x14'. I have M60 and it has more than enough bass, unless you want to have very heavy bass.

I place M60 2' from back wall and 1.5' from side wall. Both speakers are 9' apart. Since my room is almost square,i have to treat my room with bass trap and acoustic panel. My system also connected to power conditioner. THe whole thing makes M60 sings. The bass is tight and strong for most of types of music i'm listening (jazz, classical, pop, dance...)

If you have a bigger room, then M80 is better, even though i haven't listened to it , but based on the spec, M80 will be louder than M60.