mountain lion

I currently have a Quintet III 7.1 set up (bought 2 extra satellites very cheap) and am pretty happy with way things sound right now, though my room is fairly large (25Lx15Wx14h) and I think the sound could be fuller. Wondering how the B-3s would match up with the Quintet III satellites to replace the front left/right channels? Would I gain much out of this or probably not worth it? There are some really good prices on the B-3s from authorized dealers out now at half price and I could nearly make up the cost selling 2 of the Quintets. I will keep the quintet center. The consistancy(sound and looks) for all speakers is very nice now and the B-3's are substantially bigger, so that is one draw back, but if I can upgrade the fronts for minimal cost, seems like a good move. Everything is running off a pioneer elite vsx-21. Placement/mounting won't be an issue. Any recommendations? Thanks.