I have recently upgraded my fromt sound stage and now have a M7C1 centre speaker and M73 floorstading fronts, I also have a wharfedale diamond sub. It is now time to upgrade my rear speakers, I have an old pair of mission 735i's that I am using at the moment and I am thinking of changing them for Mission 77DS or Mission M7DS. Does anybody have any knowledge of these speakers? Will they give an improvement over my current set up? Where should these speakers be placed in the room i.e. on the back wall or on the side walls near the back wall? What is the difference between the 77DS and the M7DS? I can get the 77DS for £69 at hyperfi.com.