OK, I listened to them some more, and they do sound quite a bit better.
They're still not super good at the bass (which, given their relatively small size and sub-optimal mounting positions, isn't too surprising), but the highs are clearer and the mids are less muddy and boxy.
When I switch between the new fronts and the stock rears, the difference is like night and day. Those old ones are so annoying and muddy sounding!
I'll now have to get another pair for the rear,
maybe the ones that Erik the Awful recommended.
I preemptively got adapters for the rear speakers, so I should be all set once I've saved up a bit.
c