The E63 AMG S 4Matic is faster to 60 mph (hitting a stunning 3.6 seconds) and to 100 mph. The Germans unfortunately did not do a 400 meter sprint (basically a 1/4 mile) or any 60-120 km/h / 80-120 km/h testing.
Acceleration is the main advantage it seems as the M5 is quicker around track. The laptime for the E63 facelift is slower by 4/10's. The M5 was also still able to hang onto its advantage in the slalom with a 1 km/h advantage.
What about the E63's weight? Well, funny that the weight between the two cars is a wash. So AMG is able to offer a car with all wheel drive that weighs the same as the rear wheel drive BMW M5 while BMW sits around complaining about the weight gain all wheel drive would give the car. It seems the problem is not the weight of all wheel drive but that the M5 is grossly overweight to begin with.
Well folks, that's it. Mercedes-Benz caught and passed the F10 M5 relatively quickly and easily at least in raw power and the new Audi RS6/RS7 may do the same. If only BMW was not so stubborn regarding updating their M cars during their lifespan they could easily regain their overall lead as the AMG really only has a power/traction straightline advantage currently. Honestly, good for AMG and congrats on raising the bar and improving their car. BMW seems content being the Ultimate Marketing Machine these days.