Quoted from mavantix:
Hookup a keyboard/mouse/USB stick with the new wav file music to the PC, open Windows explorer on the BoP PC and swap out main_theme.wav file, it's in something like C:\brideofpinbot\1.16\assets\music\main_theme\main_theme.wav
Holy crap...this worked and to answer my own question, no -- the new audio does not need to be the same length. I'm officially pulling my game off the market for the time being.
I threw in some Carpenter Brut - Turbo Killer and it actually fits with the rest of the music pretty well. I choose to splice it up and put part of the song as the skillshot music and the rest as the main theme. The wife and I love it so far. Thanks!!!
The one problem, the sound quality sucks once it's run through the game. I used the same bitrate file as the original music. If I play it in the machine through Windows it sounds fine (and WAY louder), but once it gets pumped through the game, it sounds pretty muffled. Any idea why this would happen?
Regardless, SO much better.