Rt1Rebel

The obvious answer would be that most domestic cars are built to be 50 state compliant, and some are not. You can bet the Porsches that enter our country are different than the ones that stay in Europe. I would suspect that most domestic cars are built for 50 state compliance, but even the Mustang was/is built differently for Australia, for example. The emissions and MPG requirements of cars in Europe, Australia, etc, are vastly different.