I guess it is possible(note:he is asking for the lights,not the car).Unfortunately im not skilled at doing these things but its quite likely that someone already did this,maybe someone will post a link
I found these tailights by fluke the other day, I have no idea where. Thanks to the original creator of these RB4 Supra (like)Tail Lights (dds file). Back up your old one and replace with this dds file in your dds folder.
Tailights on skins are masked out. You have to use the dds texture to get different tailights. Dont know about headlights. That's another story.
Edit: Headlights are also in the same .dds file. I just found this out. You can't change the actual outer shape, just the textures of the Headlight Globes.