How far are the speakers from the side walls ? If they are pretty widely separated (ie close to the side walls) then moving them closer together might help a bit.
re: pulling them out from the wall further, is there any big piece of furniture between the speakers that you could sneak out another 6-12" without getting caught ? That would let you pull the M80s out into the room a bit further without anyone noticing
It wouldn't hurt to temporarily pull 'em out 3-4 feet from the wall just to see how they sound. Weekend afternoons are good for this...
I think the reason people are asking how long you have had the M80s is that it sounds like your room and placement constraints make M60s a better fit, and if you haven't had the M80s too long you could just exchange them.
