My apologies for the glare, but here's an old pic of my 07 tail lights with a light smoke tinted vinyl film from HotSubarus.com. That website no longer exists, but a very similar product can be found at Lamin-X.com. Keep in mind that if you go with a vinyl tint, the film won't wrap all the way around the inner edges of the tail lights, so you'll see a little bit of chrome (2007), grey (2006), or red (2004/2005) if you look at the back of the car from any angle.
Tinted vinyl film is easily reversable if you get pulled over, but it is honestly pretty difficult to apply perfectly. You need a steady hand to make a clean cut with a razor around the edges and a lot of patience when you're pressing them on or you'll get wrinkles and/or bubbles. Temperature also causes the film to shrink just a little bit, so the edges will pull inwards ever so slightly, so if you're OCD, it might not be the product for you.