Originally Posted by PropellerHead

I believe two of us agree with each other.

Except maybe the mud pit. As someone who's been IN a mud pit when I ran off the interstate, I think you'd have a better chance with non XDrive than with it. The reason is that XDrive is too smart for it's own good in that situation. If no wheels have traction, it'll squat. It pouts and wants to take its toys and go home. In fact, the only way I got out of the mud was to disable the system (DSC) and let the wheels spin whether they had traction or not. It was hair raising, but effective. It's this intelligence that works great in every day driving- spreading power all around all the time- but not so well in extreme situations like the snow in the video above.

I will add that X Drive not only uses braking like the earlier system, but it interfaces with the entire DSC. It senses all factors of the system to relay information to the clutches. The advantage here is that it does not have to 'wait' for wheel slip to apply brakes and then 'transfer' power (L/R, of course) like the earlier systems. It's looking for much more than just wheel spin/slip/speed variation.

XDrive and the clutches can nearly 'predict' (1/10 of a sec) what axle will need power, which one will need less, and send the power there based on inputs from ABS sensors, vehicle yaw/pitch, steering position, wheel speed, throttle position and every other sensor the DSC is monitoring. The two are in constant communication with one another with a reactive time that is so quick, it seems nearly proactive. BMW brought this enhanced level of communication to the S(a)V platform in 2004 before anyone else. Add some Eibach's to it and you'll outrun more people in the twisties than you did before.

Having said that, I still enjoy my mother in law's 2001 3.0. It's sneaking up on 13 years in service. Nary a whisper beyond regular maintenance.