I too have the QS8s for surround and the M2i for the back channel. All of them are mounted with Axiom's Full Metal Brackets. They require 5 #8-5/8 wood screws to attach the bracket to the speaker. I spoke with Eric? at Axiom and he stated that at some point Axiom would provide studs built into the back of the speaker...
I also bought some dry wall anchors from Home Desperate, they are rated at 148 lbs. The Full Metal Brackets have only two holes for attachment, so I felt the need to buy the highest rated anchors.
That said...I would have used the brackets that shipped with the speakers, but because of doors moulding, and corners the Brackets were the best choice.
I did pre drill 3/8 deep holes in the back of the speakers, and the whole thing works very well.
I used Cable Hiders from Slowe's. They are plascic and have peel off tape on the back for easy install. The one inch model will hold just 2 12 gauge wires. For 6.1 or 7.1 I would suggest the 1.5 inch Cable Hider.
Wire: I used 12awg wire from Slowe's and NXG cables from BestPriceAudioVideo.com A one meter digital coax cable with RCA plugs is $3US.
I do have a set of 2m $90US Monster Video 3 component cables and a set of 2m $14US NGX component cables, which I have done an A/B compairison with using 2 Toshiba SD4800s. IMHO there was no differance...None
