For your preferred music, I would check out a used Plinius, McCormack, and definitely ARC if you can find in your price range. The Vincent may also fit the bill nicely. Ideally you would be able to try any of these to see how well they work with your VTL and other gear.
Another suggestion is to sell your VTL pre and buy a Naim Nait XS integrated amp. This is a really, really good sounding amp and a nice match for the Quads.
Another suggestion is to sell your VTL pre and buy a Naim Nait XS integrated amp. This is a really, really good sounding amp and a nice match for the Quads.