Brent, the video quality on your HD GoPro is really excellent. The sound is very good too, when the camera's placed on the rear deck next to the engine and exhaust pipes.
I have the non-HD version of the GoPro. The video quality is pretty good too, but I can't seem to get good sound with it. My camera case doesn't have the panel in the back like yours. I would order a replacement case, but apparently the HD case won't work with the non-HD camera.
I've got a bunch of videos and comments posted on a separate thread:
Experimenting with my GoPro camera.
(By the way Brent, is your Cobra's speedo broken or did you just disconnect it to avoid self-incrimination...?)