i did that...didnt like itJust thought of another way.
If you have paint shop por, gimp or another graphics image manipulation program you can overlay the image of the decal on the car body image located in the car folder.
The decal will need to be scaled of course.
it didnt match my tinted windowsWhat didn't you like about that method? That's the method I like. The only problems I ever encounter is when the "decal" wraps weirdly or breaks up around mesh unwraps that weren't stitched or re-welded suitably. If you're not in control of the source mesh then it sometimes takes a lot of trial and error. Occasionally you can solve problems by stretching or shrinking parts of your graphic.