Hmmm, light colered car, now since i have never used Blackfire on a light car yet, this is completely theoretical. Some prefer zaino for light cars becase of its high reflectivity and optical clarity. Klasse, when used on some silvers will darken, but never the less looks good. Now blackfire seemed to darken the paint color slightly, not as much as a wax, ubt just enough to really enhance the drk green of our lexus. Also, blackfire also very reflective and "wet" so i think you should be allright uswing it on light colors abd should help them have that deep, wet look of drk colors. Ill try some out on a light colored car and post the results for you:up