I used a hacksaw to take of the bigger chunks, carved what was left into curves with a wood carving knife and then sandpapered it smooth. You could get away with just a small saw and a pile of sandpaper if you really had too.

In my limited experience, the most important thing was that the wheels where put on correctly. If they where not straight and even the car wouldn't roll as well and that had far more impact then anything relating to the aerodynamics of the body.

Jay