I have to input that Sony audio is probably par with AKAI or KOSS or whatever else you buy at Costco. Video wise I like Sony, although not as much as others. As far as the audio goes I would never use their products. Why bother when you can use Denon?

In regards to the buying group again...I believe those are intended for small to meduim retail stores not custom installers...bottom line, get some commercial space, call it a showroom, go direct with whoever you can and buy the rest through distribution channels...but I would advise having multiple distributors as not a one of them have everything a custom installer should need.