Here is a neat studiosetup used in some of my works like the Ferrari studio shot featured by blenderguru.
The file contains everything you need for recreating the light, also a carpaintnode is included.
If you wnat to use the carpaint material in non studio setups, like exterior shots, change the last glossy shader roughness from 1.0 to 0.0 to create a realistic effect in natural environments.
Thank you. I'll post the work I'll be doing with this material here when I'm done.
linolafett, thx for sharing