I have the
GoPro Motorsports HERO Wide, just the basic package and suction cup stand, no extra rollbar mount or anything like that.
My camera mounts inside a clear plastic, waterproof case. I have the option of taking out the rubber O-ring on the rear door of the case, or leaving it in. I tried both to see which gave the better sound. The answer: neither. O-ring in, the sound is muted but mostly undistorted. O-ring out, the sound is a bit louder but subject to more distortion and wind noise.
There is no jack anywhere on this thing to mount an external microphone.
I suppose I could try to record the sound on a separate device, and then try to synchronize video and soundtrack in Movie Maker. Seems kinda complicated tho'...