They put an A6 3.0TDI to the test and despite this...BMW won with his 2.0d engine...
The way things look, BMW will continue to dominate the diesel market. I own a e90 320d and i have to say that BMW's diesel engines are just incredible.
Put o chip on this bastard and he'll give a 325i and even a 330i e46 a ride for his money...not to mention cars like a supercharged C180, golf GTI MK5 and even an A4 3.0TDI.
Still I think that the 2.0d 4 cyl engine is too small for a 5 series...I'd go for a 530d for the perfect balance.