Wilson claims to stock replacement drivers for all their products, new and old. No clue what they would cost.
Ditto on the amplifier comment. Need something that swings some juice. If you are going to refresh the old watt/puppies and need a corresponding price point amp, look at new or used amps by Odyssey. While solid state, they tend to be biased for a more tubelike presentation that should mate well with those tweeters, especially if you replace them.
I am driving a pair of (admittedly much newer) Wilson’s out of their watt/puppy lineage using Odyssey monoblocks. The result is so good I have so far resisted the temptation to spend huge money on replacement amps.