Well, right now with today's technology you can 3D print multishot guns and rifles.
http://www.theverge.com/2013/5/6/4304164/video-of-defense-di...
http://www.theverge.com/2013/5/20/4348360/lulz-liberator-gun...
http://www.theverge.com/2013/8/4/4588162/worlds-first-3d-pri...
I would think car parts have to last considerable longer under stress.
I would think car parts have to last considerable longer under stress.