Speaker Question...first post on the gon

Hello. I'm wanting to put together a dedicated 2 channel system that is capable of simulating a "live" performance with blues, jazz and rock. With that being said, I value dynamics secondary to soundstage/imaging. I haven't had the opportunity to audition any speakers worth mentioning. Unfortunately, with work and other activities and a lack of dealers in my area, auditioning speakers is not even a viable option so I am hoping to make informed decisions in the used market, and with any luck find what I'm looking for the first go around. Currently the speakers in my hd (a/v?) uh, the room with my tv lol, have been pulling double duty with music. I have a Definitive setup with BP7001SC for L/R and BP3000 center and some smaller Definitive towers for rear. After much work with placement and a pair of Parasound HCA1500's bridged mono to the fronts with a small tube buffer between the amps and an H/K reciever I'm using as a pre/pro, I've managed to achieve pretty decent and dynamic soundstaging with 2 channel, for the types of music I listen to, or a decent improvement at least. I have a Parasound 5250 amp that can handle all 5 channels for movies, so for now I'm wanting to start with the 2 HCA1500's I have which are 630w at 8ohm bridged mono and use these for amplification. What speakers in the used market for $5000 or less, (preferably less :) will give me the bottom octaves at least on par with what I'm used to from my powered towers, tight/snappy midbass and a remaining audio spectrum that is musically dynamic but not fatiguing and with the ability to achieve focal imaging that essentially eliminates the sense of speakers as the source? I'm currently lookin on the gon at a pair of Vandersteen 5's (not 5a...not sure how different) and a pair of Vandersteen Quatros, mostly because I'm fairly confident that they will not disappoint in the lower octaves. Any opinions on these as well as any other speaker recommendations would be greatly appreciated. Thanks.