I saw your videos, very decent quality using this method, if I knew that before I would try it. I am a bit used to Audacity tho, I use this software to record my voice in video tutorials.
But as you said it would require a lot of dedication with synch, especially when applying slow motion don't know if my knowledge let me handle that. But thanks for the frames exporting info, that was big useful to know.
edit: Fraps lags a lot with me too, but I record multiple times until it records decently.