Someone was talking about the Tron effects, and it helped me cook up something new.
Since the RocketRods supposedly caused major structural damage to the pylons anyway, why not reroute the PM through the Autopia area so that it enters a dark tube/show building. Then, you have the Tron Speed Tunnel effects, enhanced with projectors that are actually mounted to the PM cars themselves. While I would like to avoid having a tie-in, a quick example of how this could work is to have the projected backgrounds be Dash's run through the jungle. Whereas the old system was rather random about what you did or didn't see during the speed tunnel, Dash would actually be synched to your vehicle. He could run alongside your vehicle, then speed up, run into the jungle, and when he slows down again, he is now on the other side of your PM car.