“A” is for adrenaline. It starts the moment you fire up the 3.0-liter V6 Biturbo engine—the pleasant snarl, the crackle of the sport-tuned exhaust. The Mercedes-AMG C450 and GLE450 feature an AMG-specific engine, suspension, transmission and 4MATIC all-wheel-drive system, engineered to quicken the pulse and put a permanent smile on your face.