I'm working on a car model right now and when I finish I want to get a good shader applied to it. I'm trying to get my head around it.
http://www.fotos.org/galeria/data/504/2007-Ford-Mustang-GT-fvl.jpg
What I can't wrap my head around is: It is not just a multiply (modulate) Because:
CubeMap*Black = Black.
So there are parts that reflect 90-100 percent color reflection (Green tree reflection from a black paint, sky, clouds). But yet it is not a 90-100 percent reflection everywhere because you can see there is black when the reflection would not be black. Same thing if the paint is red.
It appears as if surface normals pointing towards your eye appear to reflect less of a cubemap
http://img2.netcarshow.com/Ford-Mustang_GT_2000_800x600_wallpaper_03.jpg
Now in this image above, You see the horizon/tree line reflection in the bumper have no real color. There are some trees reflected in the back by the gas tank area and again they reflect no color.