The JBL's are genuine studio-monitors, and designed to reveal every detail a recording has in it. There was not much focus on soundstage and depth etc. If you change your JBL's for the Quad's..... well, it's hard to come up with more different-sounding speakers. In my view, if you already know that you are going to buy monoblock tube-amps, try to listen to them in combination with the speakers you fancy. I really like B&W's N802, who'll need a lot of power, so maybe tubes aren't right for them.
What I'm trying to say is that you should trust your own ears. If you want detail, go for some Revels, if you want low-end and incredible drive, go for the B&W's, and if you want all of the above, go for Wilson (and pay the price....). If you want perfect soundstaging.... well, there are worse things then Quad ESL 63 powered by some tube monoblocks. Find a friendly dealer and listen to 2 or 3 combinations, preferably with your own pre-amp and VPI. See what you prefer, buy and enjoy!!
What I'm trying to say is that you should trust your own ears. If you want detail, go for some Revels, if you want low-end and incredible drive, go for the B&W's, and if you want all of the above, go for Wilson (and pay the price....). If you want perfect soundstaging.... well, there are worse things then Quad ESL 63 powered by some tube monoblocks. Find a friendly dealer and listen to 2 or 3 combinations, preferably with your own pre-amp and VPI. See what you prefer, buy and enjoy!!