Did you make a choice?
I have just been reading Stretch's thread as I have now done another couple of sessions with the GoPro and am coming round to the idea that it is probably not the best option for RC cars, particularly if that is going to be the primary use.
It is fantastic for skiing and diving etc but I have found it a little too bulky for mounting well on the car. I would be happy to sacrifice a little quality in order to get something a bit smaller and more ergonomic.
As the clip below demonstrates, if you are going to mount it on the shell then it is probably too large, mine took a beating today when the car flipped, and there is still some vibration. Going to have to mount it on the chassis in the future.
I really like the look of the Hobbyking Wing cam, will be giving that a go in the New Year.
Hope that helps!