I bought the 150, 60's and qs8's together because they were a high gloss cherry 'special' for Christmas a couple of years ago. They were then supported by a horrendous Onkyo HTIB sub leftover that I think did more harm than good.
This last fall I emailed Axiom telling them to let me know if they 'found' an EP500 in high gloss cherry (thinking the finish had been discontinued) and they did
Funny how that works!
With no back wall (well, there is...about 15 feet back) I can't see where I'd expand on 5.1 unless you loons talk me into another sub or I start hanging rear surrounds from the ceiling.