Greg,
Welcome and congrats on your purchase. That's a very nice setup and your 3808CI will have no problems driving your system louder than you will probably ever listen, having used separates before there is a slight difference in sound to my ears but not earth shattering, I think you will be very happy with what the 3808CI will do as I have heard and read nothing but great things about it.
The Qs8's should be fine on the sides of the couch and can be mounted anywhere from ear level up.
As far as the VP150 both options are fine, I use mine below the screen with at a slight upwards angle.
