The pics look really nice.
Have you got a flash function where you can do a time exposure with a flash at either the end or the beginning of the shutter being open? I know pretty much all Nikon cameras or Nikon bodied cameras (Fuji etc.) have such a feature. It may make for some cool shots to show the car real clear as the flash fires and then to see the movement from the open shutter.
Btw, what camera are you using and are you using a tripod at all?