you could take a pair of "not so stellar" (polite-mode
) and pull out the bad parts? start small, replace the caps of the PSU, that doesn't help the caps of the ampreplace the PSU first, then amp, then the rest. IME the amps are often very cheap, and just enough for those drivers. Mind you this is no rule, just my idea of "improvement"
(and fun)
a second hand pair of Dynaudios would be in your budget. do you have some seperate amp around? you could try passive. Sometimes sounds much better.