I have a post here too about ths. NickBoul gave a lot of good advise regarding Atmos and DTS:X
My room is very close in size less the other side of yours. 11.9" x 15.6"
My M80's I sold to my son and got M22. I got two EP350 subs and the imagining is 2x better then M80. I think you will find the soundstage is about 18" below the tv. I think this is due to the fact I am only 10 ft away, whereas when they were up stairs I was 14 ft away.
Also, I had another post Alan Loft commented on regarding M22 and M80 in a smaller room like ours. I will say once you get the M80 you will find your going to set them up on Milk crates.
Also, yes if Atmos then you need direct radiating. My qs8's are leaving to my sons next month and I am getting 8 M2's 4 on wall for surrounds and 4 M2 regulars for cieling
