"Sources" have told Autocar that the coming Mercedes-AMG E63 will get "something in the range of" 600 horsepower from a "next step" development of the 4.0-liter, twin-turbo V8 currently in the C63 sedan. Since the standard E-Class isn't due for introduction until the 2016 Detroit Motor show, we're probably a year away from finding out if "something in the range of" actually means a square 600 hp when the car the AMG E63 is revealed.
Right now the E63 S is powered by a 5.5-liter twin-turbo V8 it shares that engine with the CLS63, S63, SL63, and G63, and all but the G63 get 577 hp from that engine. The 4.0-liter V8 in the C63 S is rated at 503 hp in the S model, the same as the dry-sump version of that engine that gets 503 hp in the AMG GT. Point being the jump to 600 hp isn't outrageous, and would keep up with the numbers rumored for the next BMW M5. New turbos will likely be responsible for much of that power, with AMG's powertrain chief having told Road & Track that the present turbos are doing all the work they were designed for. Depending on where the much lighter AMG GT3 road car comes in, the next AMG E63 should be the most powerful V8 model in the range.
There'll be plenty of other doodads besides, like a new nine-speed automatic, 84-LED adaptive headlights, remote controlled parking, smartphone-activated NFC-based unlock and vehicle start, Vehicle-to-X communication, adaptive cruise control that recognizes speed limit signs, and a massive advance in the suite of Mercedes Intelligent Driving features.