On #1
Another option rather than use in/on walls is to go with the on walls and bump up the crossover from the standard 80Hz to a little higher to let the sub carry more of the midbass assuming your sub is in the front of the room with the speakers. I’ve not heard the in/on wall compared to the on wall so I can’t say how much mid bass performance you would really achieve at 20 feet since midbass is best produced near to the listener. To get the midbass where I like it with my M80s I need to sit about 8 feet away if I’m listening at sane volumes (I can feel the midbass outside if I turn it up loud enough). Out at 12 feet where my seating is the midbass drops off substantially and even with my tower speakers I let my sub handle as much of it as I can.
On #2
The QS8s don’t really look that imposing. Hopefully someone can find some ceiling mount pictures to post. Also there are other less expensive options that might work for mounting. For example some of the Monoprice wall mounts might be retasked to work as ceiling mounts.
http://www.monoprice.com/products/subdepartment.asp?c_id=108&cp_id=10828They may even sell ceiling mounts.
You could also use a short drop rod for a ceiling fan or even a very large L-bracket painted to match the speakers or ceiling.
Cheers,
Dean
