It's there a video of the co-driver stuff in action? The only way I imagine it working is if the human co-driver gets a bird's eye view of the track ahead. In real life, the driver and the co-driver run the track a few times, while the co-driver scribbles notes on a pad and basically reads them back on the actual run. A real life depiction of a co-driver in the game would be no more than what you can do already by turning of the voice audio, and have a friend read the symbol on the top. That wouldn't be as fun as being able to call it in real time by seeing the track.
I think it should be noted on how the 'ol XBOX versions of the first GTA PS2 games uped the anti a little bit on the technical side. Still not ever as good as the new GTA, but stood up to par if not in some instances better than when SA came out.
ynfive's comments