I didn't know anything about the 3d expansion until i watched that link. WOW....I'm sure Pashnit or Blanca will have it soon enough for a review!
As far as sound is concerned. The camera wasn't made (and I don't know of ANY on the market), that can handle sound at both normal conversation AND at speed on a motorcycle. That's why most edit down the sound levels and sometimes add music while editing. Using the waterproof case, mounting with no or clean airflow, vibration-reducing mounting, and mounting near what you want the camera to hear (in this case I suspect, engine noise) is important. Also look for turbulence in front of the mic.
As far as sound is concerned. The camera wasn't made (and I don't know of ANY on the market), that can handle sound at both normal conversation AND at speed on a motorcycle. That's why most edit down the sound levels and sometimes add music while editing. Using the waterproof case, mounting with no or clean airflow, vibration-reducing mounting, and mounting near what you want the camera to hear (in this case I suspect, engine noise) is important. Also look for turbulence in front of the mic.