Mercedes did not just stick the standard 4Matic on the E63, they tailored it to AMG. Head of AMG development Tobias Moers stated, ""We completely reengineered 4Matic to make it work for us." This means the torque split between the front and rear wheels is 33/67 for the E63 AMG all wheel drive unlike 45/55 in the standard E-Class 4Matic. The desire obviously to maintain the rear wheel drive character as much as possible.
Not only that, by by removing all three electronically locking clutches in this version and reducing the size of the rear half-shifts the weight gain penalty will only be 44 pounds. That means with all wheel drive the car will still weigh about as much as the F10 M5. Not bad at all.
The M157 engine is getting a boost to 575 horsepower, more than the 550 offered by the Performance Package today. This appears to be done by more than just software with some hardware changes to go with it. The horsepower number will vault the E63 AMG ahead of all challengers.
The downside? No dual clutch transmission, the 7-speed automatic remains. Fairly disappointing as Audi, Porsche, and BMW offer dual clutch transmissions. It certainly is possible that the new Audi RS6 will be able to rival the E63 AMG. Regardless, with all wheel drive and more power the E63 certainly is raising and set to take the throne.