I tinted my tail lights but I did not go super dark. I did it dark enough to notice and did wetsanding in between coats and then did clear coats. Basically they were glossy enough that they looked alot darker than they were. I have followed my car at night from various distances and never felt that they were a danger. You could still see a lot of light. I also did my brothers quite a bit darker than I intended but when he hits the brakes you can still see the brake lights as plain as day. If I were you just do a slight tint. Usually its enough to look good but yet you can still see the reflectors in the tailights when your car is sitting on the side of the road.
