This video commentary was worth five minutes of my time:
It might be worth your time. I'm not sure I buy his explanation for why the US government won't let these cars be sold in the USA. What do you think?
Still getting double the gas mileage of the USA's fleet with existing European auto technology seems noteworthy. Suppose Peak Oil kicks in with something like 4% less liquid fuels per year available to the USA citizen. A doubling of mileage would mitigate Peak Oil for around 18 years. That's substantial.