Does anyone REALLY know how the R AWD decides when and how much power to shift to the rear? Of course it's when it detects rotational differences of the front and rear wheels, but exactly what other info is the computer gathering? If the g force and steering wheel angle tell the SUM it cornering, does it then direct power rearward? But how much, 20%? 50%? For how long? I'm just curious what makes it different from say a S60 2.5T AWD.