wellllllll id get a blank circuit board and bust out the solder and soldering gun nad get to work lol it kinda depends if i went with colored leds or white and left the colored lenses in my tailights. but either way id be cutting 1/3-2/3 off the back of hte taillight off to retrofit the circuit borad withte leds that i would put on it. id solder them all in parallel and then tie them into the tailight harness. (brakes, blinker,reverse). my only concern if i did that would be if the difference in dimmness between tails and brake woud still be evident.
ya ive heard that if you get rearended wand have tinted tails that your screwed. it says right on the can of niteshades "FOR OFFROAD USE ONLY" and then i think it also says to check local laws to see if it may be legal in your area(aka the 99.9% chance says its illegal but they wana make ytou look stupid anyways when you ask someone at a police station or like the DOT). mine are reaaaaallly dark.... im still wating to get pulled over for them before i wetsand them to hopefully remove some of what i put on and let a lil more light through