Best lower midrange unit - replacment for KEF B110

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 lower midrange units? Which model is the best? The old lower midrange unit was a KEF B110. A Thanks