Same boat re: audio speed. I actually speed up the voice in the backend by 1.16x . Above that I was getting too many artifacts in the audio. The nice thing about doing it at that point is that I can handle the music and the voice separately, i.e. the speed of the music stays unchanged.

Speeding it up in the player will also speed up the music, which is not very zen. But I guess I'll just add it to the player and let people decide how fast they want to go.