2013 Mercedes-Benz GL63 AMG packs 550 hp

Mercedes-Benz is adding a fire-breathing AMG variant of the GL sport-utility vehicle for the first time for 2013.

The people hauler will pack a biturbo 5.5-liter V8 rated at 550 hp and 560 lb-ft of torque. Code-named M157, it's capable of propelling the ute to 60 mph in 4.9 seconds en route to an electronically limited top speed of 155 mph. The engine works with a seven-speed automatic transmission and permanent 4Matic all-wheel drive.

There is also an eco stop/start function that comes on in the controlled efficiency mode.

The GL63 debuts in the first quarter of 2013, capping the updated GL line that arrives in September. That's comprised of the GL350 Bluetec diesel, the GL450 and the GL550.

By comparison, the AMG model makes 121 hp and 44 lb-ft more than the GL550, which employs a 4.7-liter biturbo V8.

Design cues of GL63 AMG include flared fenders, large air intakes and chrome, accented by LED daytime running lamps. It rolls on 21-inch wheels.

Other standard equipment includes AMG stainless-steel running boards, floor mats and pedals, bixenon headlights and Mercedes' attention-assist system.

By Greg Migliore