First, there is no center diff, just two drive units, one at the front and one at the back. There is no set torque split, meaning that there isn't always at least 10 percent of power going to the rear wheels, it's constantly variable. When you set off from a standstill, it automatically transfers power to the rear depending on the level of grip available. If the front tires have no grip, 100 percent of the available torque can go to the rear wheels.
It also has torque vectoring on both axles. In the front, it's brake based while the rear end can actually overspeed the outside rear wheel to mitigate understeer. We were told that the vectoring on the front wheels is rarely used, it's really only there to assist in a moment when the car is extremely upset, mostly from the driver being too aggressive.