I used to have a huge problem with coloring a car to a different color. I had an idea to kind of fix the problem. its sort of like the air brushing.. i'm not sure if this is a well known thing but it could be useful for someone who is having the same problem.
Here is the original color.
I selected all the areas i wanted to be red. This is how it turned out.
I set the layer blend mode to "overlay" but it still seemed too red. didn't look very realistic.
So i selected the areas that should have been lighter (a few at a time depending on their location), went into "refine edge" and gave it a bit of a feather.. grabbed the gradient tool with a gradient from white to transparent with a rather low opacity
The final product
*I know its not perfect. it was sort of rushed. but it does give a pretty general idea.*