bcredliner - I'm not too concerned about the engine power band. The 3.0 has plenty of power for me and I'm not trying to win any races. I rarely tow my load over 65 mph.
At this point, I'm more concerned with differential revs per mile front drive to rear drive and any affect on my Mechanical (Non-Xdrive) transfer case.
Searching this site, online, youtube videos, my owner's and Bentley manuals, . . . I can't find a detailed explanation of the transfer case's ability (or inability) to mechanically adapt to differential front and rear axle rpms. I figure that it must be able to . . . otherwise anything that throws front to rear tire diameters out of sink (tire pressures, hvy rear load, hvy front load, . . . perhaps even as experienced during heavy braking) would cause a binding stress that would greatly reduce mpgs, or worse, strip TC gears. If this is this the case, tire pressures and absolutely even tire wear are critical.
So, what am I missing? What is the component in the drive train that allows for different front and rear drive axle rpms? If this component only allows for a "slight" differential in the rpms, what is the tolerance, and how would it most likely fail if the tolerances were exceeded?