I think you mean Diesel (diesel oil/fuel) is higher than gasoline. Even with diesel being 20-30 cents more per gallon than gasoline, a diesel engine will always provide greater MPG. Look at the Mercedes E320 Bluetec diesel...it will deliver about 700 miles per tank, where the gasoline model delivers maybe 300 miles.

With the X5 being so big and heavy, and both the 3.0si and 4.8i deliver truly dreadful/horrific/tragic MPG...I think Fall 2008 is too far away for diesel models!