I haven’t really needed RPC cars for rendering purposes ….YET.
However when I wanted to render a car (Other than the yellow beetle), I got horrible smudge marks all the way down the side of it.
So by going to the Properties of the RPC Car and editing them,
you can adjust the speed of the car, the Viewing height etc.
I also noticed that the car wheels do not have to be straight. You can adjust the steering.
Cool finished product