I decided to paint my tail lights because I was going to use the euro rear license plate filler, which creates a dark line across the middle of the rear in between the tail lights.  For added effect, I decided to paint my tail lights to match.  I used Testor's "Transparent Window Tint" paint available at hobby shops.  I used Transtar Kwik-finish automotive clearcoat for added protection.  They came out very glossy.