Steve, I owned the Jolida 302b amp as well and went towards SET and more efficient speakers.
Before you upgrade: What tubes are you currently using? I did have significant improvements tube rolling. Otherwise I think you have to spend significantly more to improve on the Jolida.
Anyway, some things I considered before going the low power route:
AES Sixpacs
Quicksilver Monos
Rogue Audio
and I heard this one recently
Almarro A318B SEP amp - 18 Watts but incredible sound driving a pair of GMA Callistos which are a bit more sensitive than your Vandersteens though.
With best wishes,
Rene