Speaker placement is the key. Play around with it and see if you get better results. Use a tape measure and a big dry-wall T Square to help you get exact placement. You'll need to consider the distance from the front wall (the one behind your speakers), the side walls and the listener position. You'll also need to consider speaker toe-in and tilt. Do you have the instructions that came with the Vandy's? If not, I think its on-line at the Vandersteen site. Richard is pretty specific about placement.
Once you have your speaker position optimized, you can consider electronics upgrades. But I think your wasting your money with electronics until you first get speaker placement optimized. The only caveat may be the Dual TT setup. I'm not familiar with that TT and you don't mention what cartridge you're using. Is it the only source? Do you have another source you can try? Does it produce the same soundstage issue you are hoping to resolve?
