I didn't look at all the links, but I wonder if they account for the 10% ethanol that is in many gasolines now (and decreases the btu content per unit mass of the gasoline)?
I am not sure I'd buy a diesel X5 unless I was going to routinely travel long distance or, better yet, tow something. I love diesels, don't get me wrong, but with the advances in the twin turbo gas motors, it's getting tough to justify any "savings" by using them. The VW Jetta TDI's perhaps being the outlier due to their small displacement and ridiculous fuel economy numbers.
Are the much better 4.0d numbers mostly due to the 8-speed trans or some other features? These are intriguing numbers.
Now, for a really interesting argument, go into the true "green-ness" of a hybrid, especially considering battery manufacture and recycle.
Also, I
over discussions of "green-ness" and any sport activity/utility vehicle.
