I am building my home theater and need advice on a sub and back surround speakers. I have the following components: an Onkyo 706 receiver, 2 Boston Accoustic HS 450 Tower & a HS 225 center speaker. I was told by a crutchfield rep that I needed to have Boston back speakers to match my current setup due to tone. I'm not a fan of the rear Boston speakers (they're pretty bulky) since they will be mounted behind the couch. I'm looking at $1000 for the remaining components. My room is 14 x 16 and carpeted. Thanks!