Nobody talks about adblue. On the X5 diesel, after a few years, like when the warranty expires, you will have to face the adblue fill up. Do the math and you will see that you will be paying more in the long run for the X5 diesel. The X5 diesel is deceiving when we talk about mpg. For now, with todays fuel prices, you are best off driving the X5 petrol. I personally love diesels and will probably purchase one this fall.