Simple, the EPA, that communist organization has stopped many diesel ventures in the US, I know a guy who works on the diesels being designed for the future, 98% of the prototypes he tests and tunes are going to Europe, not only will they blow the doors off of anything here, they get over 40 MPG. He was testing out a Dodge Nitro diesel, brought it home, wicked sounding engine, there are single and dual over head cams available.