I don't know if I'd say the M80s were "too big" for your room. If you had a burning desire for them, I think they would work out OK. But, the M60s will give you all you need, and then some, in a room that size. I have the 60s in a room 11.5x18x8 with a 10x10 dining area adjacent. They do the job, believe me.

Jack

"People generally quarrel because they cannot argue." - G. K. Chesterton