Interesting point, I think somewhere implicit in my question was this, what is the optimal power/efficiency tradeoff range of revs? (I imagine this has something to do with torque and horsepower curves, but that stuff is generally beyond me.) Just curious, but do you know if the 2000-3000 rpm range is something that BMWs are engineered to, or is that a general rule of thumb for internal combustion engines?
One other point concerning highway driving-- I am rather amazed that BMW 6-cylinder engines are so efficient in the range of 70-80 mph, delivering honest fuel economy figures around 30-32 mpg, on a par with if not actually better than many so-called "economy" cars.