I wouldn't suggest trying to re-sync using the mix already posted, since that recording's L and R tracks were adjusted during re-recording in order to try to stay in sync -- they wouldn't match up naturally if you split them apart and then tried to re-join them in the computer, not without a lot of fine-tuning throughout.

You'd need to go back to the original sources, record each separately, and then pair them by matching specific fixed points (a piece of dialogue, a laser blast), adjusting speed accordingly. Still not an easy task.