This is a really interesting topic actually, about the differences in cars between europe and the states.
Catilityc converters are a good example, they have only become mainstream on cars since about 1990, before that you could have one as an optional extra. A rear fog lamp is required on UK spec cars as well, it has to be fitted on the right rear of the car.
One other sticking poing for US cars being imported over here was the indicators (turn signals) On a lot of US cars the indicator flasher and the brakelights were one unit and coloured red. This is illegal in this country as flashers have to be orange.
Lots of silly rules!!