another thing I've heard of (and really want to try when I get a chance to) is to follow the car in a Jeep/SUV with a pop up rear window and use a gorillapod tripod on the edge and shoot from inside the trunk (and possibly shooting out the rear seat windows as well). that way you can get full car shots of the front and sides of the car... possibly even the rear too and have full control of the camera on the fly (plus its less of a risk of having it smash into pieces all over the street.
kinda like this...
