It's essentially impossible to tint lights without reducing the light output; I can't believe this even needs to be point out.I would not tint headlights, but I would, and have tinted tailights (spray). Nothing ridiculously dark. Part of the motivation was to see how it would turn out and hide a crack, maybe some boredom. I eventually replaced the lights. Replaced the marker lights too, as one of them went out, with a tint. I don't think I've reduced the brightness at all.