I'm a huge 3D printer advocate and hobbyist but...this doesn't really make sense to me. VW (and arguably a lot German based companies) are super in-sourced based. I wouldn't be surprised they have a dedicated plant just for injection molding and they probably make their own tooling in-house. I don't see how 3D printing would be the best choice for their infrastructure. They probably could get usable test shots within a week with the right people working around the clock.