I think if you can do some voice training about prosody and resonance, but not training any pitch changes, it would improve your post OP experience. If you go in untrained, you may otherwise be disappointed by the surgery because your voice will essentially sound very similar post-OP, just with a bit higher pitch - to fully use the pitch gain you actually need to use the proper resonance, so I think it helps to have an idea about voice, resonance, voice modification and all of that. I think it helps if you know how to play around with your voice, go up and down in pitch, use different resonances and just be more comfortable experimenting with the voice - this helps during the post op phase when you basically have to experiment with your voice to find out how it works now...