I am due to replace my BMW 330 diesel coupe this year. I drive around 20,000 miles a year, mainly on motorways. With the gap in prices between petrol and diesel widening, I have started to question whether there is still a benefit in having a diesel car. I have done my own calculations on fuel usage which seems to suggest there is still a financial advantage but when I look at one of the online calculators, which takes into consideration car tax, servicing, etc, it seems to suggest that petrol is the way to go. Then which car to choose? I have loved the silky engine in the BMW as well as its size.