Owned TC 50s in the 90s, loved them. Did surgery on the crossover by simply upgrading the caps and the wire. They jumped considerably in performance, I mean REALLY jumped.
So you can keep them, upgrade them and continue to love them. Otherwise, I'd consider a pair of ATC SCM 20s for a meaningful upgrade. The ATCs can also be pushed much harder than the TC 60s which tended to have fragile tweeters.
Best of luck in your quest.