If I were you, and you just want a quick change in color (not a slow change over time), just make another skin instead of using the entity.light or materials. You can just change the yellow to brown with the free GIMP (www.gimp.org) program with the selecting by color button, then you can change that selections color (either with a hue change or by just painting it directly). Then you can keep the same color for those little logos on the car. To change the skin of the car, just put my.skin=2 in your script. Thanks!