Mark, I don't think you meant stereo "mode" because the surrounds are silent in that mode and only the mains(plus sub)operate. Stereo source material can and should be played in a mode(e.g. DPLII, Logic 7)which steers ambience to the surrounds. For that use very wide dispersion surround speakers, such as the QSs, would have an edge, since no specific instruments are actually discretely located in the surround channels, just their reflected ambience, which should be widely dispersed rather than narrowly located.
