What kind of emissions do the 75 MPG cars have?
That is something to know.
I am thinking the consumer here will be slow to pick up diesel because of the past 'failures' seen in the US. There are some good quiet diesel cars now, but they are few and far between (Diesel Mercedes and VW for instance)
Diesel may have more visable pollution, but is it worse off than the NOx and other fun stuff out of a car exhaust?
I have more questions than productive thoughts on this crazy topic.