The eye is more easily fooled than the ear. Syncing audio to video is much less onerous, a mis-sync of 30-40ms can go unnoticed by most people. Syncing two audio sources is more difficult, a tiny amount out generates an effect called "phasing". While this is used for cool effect by DJs playing dance music, it's not something you want to achieve here.
Not trying to piss on your bonfire, but coupled with the fact that a professional audio engineer is doubtful that it can be done, I'm just sceptical about your "piece of cake" claim.
But hey, don't let that stop you, I could be talking crap. Grab one of the MP3 files and have a play with a short section. If you can get a phase accurate left/right sync, then I'll take it back.