I was looking into buying a set of HIDs from a used Passat. It says it came from a '03 Passat w/ gas discharge. What exactly does that mean? Also, what year did Passats start using the tailights with the white in the center, becuase I have a black '99 Passat and I don't know if I should get new ones with the white, or keep my all red ones and get them tinted.