I converted a car from rFactor so it can be placed anywhere in your venue to check that things are a sensible size. E.g. if you're making a fantasy track you can use the car object to make sure the pit garages are a decent size.
http://www.racedepartment.com/downloads.php?do=file&id=2615
http://www.racedepartment.com/downloads.php?do=file&id=2615