Clay, welcome. Congrats on getting the QS8s; you're highly unlikely to be disappointed. As to installation, in general mount them on the side walls about 3' above ear level and slightly(maybe 2')farther back than directly to the side of the listening position. This helps add a little phantom back surround effect in the absence of actual 7.1 back surround speakers.
Don't forget to make full use of your new setup by using DPLII or similar processing on 2-channel material. This takes the natural surround ambience that was picked up by the microphones and then mixed into the front channels(there was no place else to put it), extracts it, and sends it to the surrounds where it belongs, making music listening significantly more realistic and enjoyable.
