GM Is Getting Ready to Put 3D-Printed Parts in Its Cars - Kinda surprised they weren't already - you can get retro car parts 3d printed like tail lights already.

That is surprising. I knew they used them for prototyping, but I guess I assumed they used them for more than that. IIRC, Jay Leno was an early adopter of 3d printing for replacing classic car parts that are out of production.