tint is going to fall off...think about it, window tint is usually applyed from the inside of the window for a reason.
night shades is good but if you dont know what you are doing, it is easy to mess up and it will turn out nasty
best thing if you want the whole tail light dark is to buy that 3m film and lay it on the lights. (the same stuff you would lay across your front end to prevent rock chips, it comes in clear, light tint, dark tint, yellow, blue, etc). if you do some research, there is a guy on here selling those pre-cut kits for people wanting to over-lay their tail lights, headlights..etc.
03.5-dc-speed: you should wetsand your tail lights with 1000 grit paper and lay on some clear coat on top of that...the difference will be very nice