Hey man! I just saw you posted all those comments on pictures asking about what was used to tint tail lights. People use VHT Niteshades (
VHT Nite-Shades™). You have to sand the light down a little, spray it with 3 or 4 coats of this stuff, clear coat it, then buff it out until it shines. Ofcourse it's more complicated than that, but that's the general idea. Good luck if you decide to do this! It's one of my favorite mods!