You can't go wrong with the upgrade, Eleven P engine elevates Pacific in every way. It's more open, with better micro dynamics, but still smooth and musical.
It's like upgrading the platform, but your favorite selection of tubes will still dictate the sound signature, so no need to worry there.
I went all-in with tubes as well, Valvo g2504, dual Siemens EC8010 Gold Pin, and 2e22 output tubes. Of course all of them in TP adapters, it's a phenomenal combination of clarity, space, and timbre that makes DACs like dCS or Esoteric sound like a lab measuring gear and not music reproduction.