Cars for Vdrift are made with a program called Blender, it's free and downloadable here:
http://www.blender.org/cms/Download.13.0.html
Here's a link to a car modelling tutorial.
http://gauravnawani.byethost7.com/tutori...yota1.html
With this tutorial you will make a Toyota Celica. If it's finished it can be imported into Vdrift with the import script.
A few things to remember are:
Try not to get to many poly's 5000 is probably good for the whole car and 1000 for a wheel.
Build triangles and not quads.
If you need any more help you can always come onto IRC.