Mercedes-Benz had barely taken the wraps off its new S-Class before it also announced the high-performance AMG version of the flagship sedan. Usually, a manufacturer will introduce a new model and then either six months or a year later add variants, to keep interest high on the entire product range.
The all-new S-Class debuts as the S550 in October, followed a month later by the 4Matic all-wheel-drive version and the S63 AMG, which also has all-wheel drive. Power comes from a twin-turbo 4.7-liter V-8 that mak…