Car photos tend to look better if the frame is not too tight on the front, especially if there is motion, or implied motion in the shot.
If the entire car is visible, I suggest you ensure that there is more space where the car is about to travel, and less inclusion of space where it has been.
If the car is cropped by the frame, and it looks like an accident in the eyes of the viewer, then the photo will lose points. If the intersection of the car with the frame looks quite deliberate and "feels good", then the cropping is fine.
Finally, look out for:-
Distracting elements which take the eye away from the intended subject
Unfortunate intersections between your subject and the background
Generally too-tight cropping, however, it's good to get in close
Use the rule of thirds if it fits the situation
Discard the rule of thirds if you're going for symmetry
And all rules should be broken to see what happens. The result may be good!