Best treble unit - replacement for Audax HD12X9D25

I have a set of excellent twenty year old speakers. They had a list of $ 5,000 in 1984. Rather than to spend silly money to purchase a new pair, I am thinking of purchasing new speaker elements (treble unit, upper midrange, and lower midrange) and to upgrade crossover -. This is a four way design. I just purchased a NOS woofer; since there are no 11 x 14" woofers made these days (I use KEF B139) (at least I did not find any). Which manufacturer produces the best treble units? Which model is the best? The old treble unit was an Audax HD 12x9D25. Thanks
My response to yr other post applies here too -- BUT, possibilities here are more open. Check out the parametres of yr Audax (google it) and look for a suitable replacement -- i.e. a tweet that has similar, if not identical, characteristics.

The tall & short of it is, if you change the original drive units used in this spkrs, you're best off redesigning the xover. That's a tall order: you'll have to match new units, mated them via a new xover, all of this in an existing box...
Unless you like that sort of thing (it can be fun -- & frustrating too). Cheers