*EDIT - Sorry I forgot two important things. Read it again if not your first time.*
Try this...
Draw a sphere in modeler as big as it will cover your car (left menu under Create tab, select "Ball"; hit "n" - means Numeric - and insert 1 km radius in all axes. Set the origin so that your car will be in the center).
Delete the bottom part and now you have your Skydome. Now hit "f" (Flip the normals, so your emisphere will "look" your car).
Hit "q" (Surface), call it SkyDome.
Now open the Surface Editor (left menu), select the SkyDome surface. Increase to 100% the LUMINOSITY, check SMOOTHING and leave all the other stuff as it is.
Save your object (SkyDome.lwo ??) and send it to Layout.
Now in Layout select your Light and hit p (Properties). UNCHECK "Affect Diffuse" and "Affect Specular". Now click in the same panel the Global Illumination button.
In the panel that now appears CHECK "Enable radiosity" and choose MonteCarlo. Leave other stuff as it is.
In the top of the view you can see various tabs. Hit CAMERA. Now the left menu will change. Find ANTIALIAS and hit that button. Set it to medium (9 passes). If you want hit the Enhanced button right under the Antialias one. It will refine the render but doesn't increase the passes.
Now you can F9 for your RENDER and... prepare to wait !! :roll:
Radiosity costs, but the result will be cool.
Post the image !!!
Tell me if something is not clear. Bye.