The CS-63DX was the TOTL (through several offerings). It is bigger physically than the CS-99A. Personally, though, I thought the 99A went a bit deeper in the bass register.
A good ol' speaker system, though. Good to hear that someone is still using a pair!
I have had the CS-88A & CS-99A, and the HPM-900 (replaced the HPM-100). I really liked/like all three, but the HPM is just a bit more refined.
One could definitely ROCK OUT with the 63DX.