Denon is saying that there receiver works fine when you are in stereo but recommend 8 ohms speakers when you are listening to music in 7.1 stereo or listening to a movie in 7.1. Should I be worried about that?

Also, what do you think of putting M80's as surround compared to the QS8 ? The QS8 envelop you as surround speakers, would the M80's do the same?

Sylvain