2000 - 3000 is the average "cruising range" (low end of the horsepower/torgue range) for BMWs. If you notice when you're doing hwy speeds 55-70 mph - that's your optimum milege range but also the low to low mid torgue/hp range. Rear gears have alot to do with it but mfgrs have to compromise for all around drivability.
Just for laughs take it out on the hwy & note what RPMs are at 65mph - then compare that to what your red line is - 6800rpm or so? I'd guess around the 2800RPM range is your 65mph zone and at that the motor is still napping...lol