It was federal law.
http://www.motivemag.com/pub/feature/tec...an_Lights.shtml

Only very few US Porsches already changed to the European style, like on the black 1985 Targa in the pic. I also don't like the shape of the US lights on Porsches at all. Another story regarding my wifes 1976 450sl. There I like the Merc US double beamer much more than the German rectangle headlights.

'14 4/4 graphite grey