Your current Qs8's should be used for side surrounds whether you have a 5.1 or 7.1 setup. Many people call them rears. I prefer Qs8's all the way around for music and movies, their great. You could get just one Qs8 for 6.1 for now since most rear channel dignals are not seperated anyway.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85