This mod has been updated and now works on all vehicles since version 2.0.
To make the glow work, add the "Ashmakers Lava Glow" paint design to your car -> go to the "Color" tab and select the base color for "Color 1", then set a lighter color for colors 2 and 3, to make it glow.

Colors:
Blue
Pink
Red
Green
Violet
Darkside 
In version 3.0:
- Fixed a small trailer.