Straight 6 DOHC 24V Diesel. 2000-on. 132kg 291lbs
This isn't the exact engine from BMW that they use now, but this is a straight 6, 3.0 litre turbo diesel engine, weight 291 pounds (found on a BMW forum, so I am not promising it is correct) which is probably engine only, not tranny / clutch assy.
That seems fairly light! A modern diesel might be a bit heavier with the urea burner, but only a few pounds. Oh, and I rechecked the specs- 265 HP and 425 ft pounds! I know a 2.4L can achieve the MPG, but there is no way it can get that much power AND achieve the MPG. The best part is, max tq is reached at 1300 rpm.
I am not here looking to gloat about the BMW engine, just wondering what are the possibilities?