you know, bmw has the best diesel engines in the market and probably also the best 6pot petrol engines.
To be the best doesn't mean to be the cheapest, in other words, they want heaps of money for their perfection.
You pay, you do the math.
I did, and I did the comparison with 320d, which I tested, as I did with IS220d. In day to day life, I would get 0,5-1,0l better consumption per 100km with the bmw. In your oldstyle measuring methods it means that at the moment I am with IS220d on 41,9, with beemer I would be on 45,5-49,5 - which I doubt but OK, let's to do the math with the worst case.
The difference in money means I would pay at worst 1 € extra per 100km.
When I was buying my car, the difference with 320d was about 10.000 € (talking about the same equipment level)
If I bought 320d, I would have to drive 1 milion kilometres, just to equal the ownership and running costs. But, as I lease the car and I have insurance, I would be paying about 25% extra on interest and also I would be paying extra for the insurance, because it is more expensive car and it is being more often stolen - so even after 1milion kms I wouldn't be on even.
Of course, you can buy bmw without the toys and gadgets and you will be on equal price from the beginning. The question is, do you want premium car to be in luxury and feel luxury or you want just look good in front of your friends and neighbours?
The competition in family sized cars is now very strong, with cars as mondeo, new C5, mazda 6, insignia, accord... if you want to save every penny, why did you buy premium car?
It is your money, your choice, but I guarantee you that with 325d you won't save nothing.