My son had an Audi A4 diesel and he did a huge mileage in it at very high speeds (mainly across Germany). He now lives back in England and has bought a BMW 330 petrol, (despite working for Mercedes F1).
I don't know about servicing costs on my BMW 730D as I do it all myself and just have to pay for the parts. The only time it went for major work was when a blocked sun-roof drain caused the carpet to get very wet and it shorted out the 'Yaw Sensor'. That cost £800 to replace with the re-programming and the necessary seat & trim removal.
My wife has a 325i SE petrol and she had a VANOS cam timing unit fail and it cost around £500 at a local BMW specialist.
I have had BMW's since 1980 when I finally got p****d-off with Jaguars after the unreliability of my new-in-1977 XJ6C. Currently on my 5th 7-Series and have had 3-Series & 5-Series ones as well. The M535i I had in 1986 was simply fantastic at the time.
Grandson now has an '02 plate 318i SE with just over 100k on it. I drove it the other day and it is so nice to drive. The road-holding is great and the handling fantastic. To think he only paid £580 for it is amazing and he has spent very little on it. He managed to change the horrible 19" wheels which were fitted for a set of 17" and the ride is so much better. He gets over 34 mpg as well.