I was recently watching a youtube video on TL mods and stumbled across these and was curious if anyone knew which LEDs to use and how to install. Thanks!

 

Have you tried reaching out to the video's owner ?

 

Find a thin LED bar/strip that is the approximate size of the reflector (but slightly smaller). Remove the reflector from the car. Cut a small slit in the side of the reflector. Insert the led strip through the slit you cut in the reflector. Seal it back up with glue or epoxy or whatever. Then wire the LED up to your brake lights and reinstall the reflector.