Reply #3: It's a shame you didn't look further

[Savannahmann]

If you had, you would have seen this tidbit. http://autos.msn.com/advice/article.aspx?contentid=4024642

The Catch
Geography can be conspiring against eco-conscious buyers. The PZEV's limited availability is not a result of sales volume, marketing or any other political force; it's all about fuel quality. The reformulated fuel available in what's called the California Emission States—California, Massachusetts, New York, Vermont and Maine—make PZEV possible. Take a PZEV to Kansas and the change in fuel quality will knock down its emissions performance. Many PZEVs like the Ford Focus may be available in states bordering the California Emission States but in the case of Ford the 130-hp DURATEC 20E engine is a no-cost option.

With the engine tuned to a specific fuel mix, the engine could be damaged by the wrong fuel mix, and here is the neat part, the emissions could even be worse depending on the fuel mix. Oh before you start to say standardize the fuel mix think about this, the fuel mix is standardized by the Feds, but the states have added to that, which means that only in those states that have special more expensive fuel is this car possible. Wait there is more. In California, you don't have additives to make the fuel winter friendly, which you do in New York. (I don't know what those additives would do to the engine so finely tuned I doubt the car makers do either)

Remember that this is an opinion piece, and probably not considered in a scientific manner.