It never ended Ferrari, Porsche, and Maseratis from selling cars in the US. They just pay the penalty.
"A number of manufacturers choose to pay CAFE penalties rather than attempt to comply with the regulations. As of model year 2006, BMW, DaimlerChrysler, Volkswagen, Ferrari, Porsche and Maserati failed to meet CAFE requirements.[24]"
http://en.wikipedia.org/wiki/Corpora...e_Fuel_Economy