Actually it's only a colored copy of the chassis.(That's why the lightning always look right )
You know Shell(Gaz station company), the decale have 2 color. So technically you have to use 2 copy of the chassis layer to do the Shell logo one your car.
Here an example how I proceed when I color my cars.
I think you didn't understand how I make decale. Or maybe you're lazy!
I usually put the Decal on pic & distorted to get it in the right angle. I create a white layer to be able to select the the decale.(lol, confusing there huh, lol)
Your decale should be in the last layer & the white layer should be just under. Now you should see only a white background & your decale there. You must wonder why I use white huh? Cause most object have a color. with "Select->Color range" you should be able to select the decale(put the color range to 100 quite effective). Check "inverse" & choose the white color, after highlight the body layer & do copy-> paste.
Hide the white layer & the old decale(the 2 last layer). Just above your body layer there should be there a layer. Highlight it & play with brightness & contrast on it & the Hue/Saturation.
That's how to do decale in the lazy way. You can also select each color of the decal & do copy past over the body.
Sorry READ THAT AGAIN It have been edited!!!!!!!!!!!!
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