I might suggest going with 5 M2's and 2 or 3 wall brackets based on your budget. If you are able to place an M2 right on top of your television for your centre channel that would work really well (if not you can wall mount it slightly above your t.v). The rears you can wall mount as well.
This is a little over the cost of a pair of QS8's but overall this might make for a better overall improvement in your system as a whole depending... (I am not exactly sure what you are using currently or your room size
)
In the meantime you can save for 1 or preferably 2 quality subwoofers (entry level Axiom, HSU, SVS subwoofers). This can make for a great system IMO and perfectly timbre matched might I add :).