There is something extremely rewarding about driving a sleeper like the 2013 Mercedes-Benz GL63. You're stopped at a red light and you see a dismissive look on the face of the guy in the BMW 3 Series in the lane next to you. Then the light turns green -- and you're gone. What may shock the sedan guy even more is that you're driving a sport/utility vehicle that doesn't look like the hot rod it is.

This hypothetical circumstance is one we experienced repeatedly while behind the wheel of the GL63. It's hasn't undergone as much of a styling makeover as the rest of the AMG line, yet its $128,000-plus as-tested price will provide the performance fun of an AMG without causing Johnny Law to give you the stink eye as you drive by.

As is the case with regular GLs, this is a three-row sport/utility vehicle that comes with all-wheel drive and has a towing capacity of 7500 pounds. However, the off-road package isn't offered in the AMG model and the vehicle has a low front air dam, so backcountry expeditions that travel over anything tougher than dirt roads are a no-go.

That didn't keep us from enjoying the rest of the amenities the GL63 offers. Power comes from a 5.5-liter twin-turbo engine backed by a seven-speed automatic transmission. The engine puts out 550 hp and 560 lb-ft of torque; thanks to that, plus the sweet-sounding AMG-tuned exhaust, power flowed freely throughout the rpm range. The exhaust makes wonderful growling noises and terrific throttle blips when downshifting. It sounds like a sports car, something few three-row SUVs can boast. The transmission is smooth, with only occasional harsh shifts. Ride comfort was actually better here than with the non-AMGs we've tested. Despite the vehicle's size and weight (5787 pounds), the GL63 handled better than we expected, and better than a vehicle this size should. There wasn't a lot of body roll, and it felt stable.

At the track, its 0-60 time was good, but not earth-shattering. It hit 60 in 4.7 seconds, which is 0.1 second faster than the last BMW 335i we tested, but only 0.4 second quicker than the GL550 we tested at Sport/Utility of the Year. Yes, the GL63 is faster than non-AMG GLs, but not in the head-snapping way you would expect in an AMG. Its quarter-mile time was also quite respectable: 13.1 seconds at 108.3 mph. Even though we used words like "good" and "respectable" to describe the vehicle's acceleration, we can use the term "phenomenal" to describe the Mercedes' 60-0 braking distance. It only needed 104 feet to stop. That is comparable to braking distances Motor Trend has recorded for sports cars, and is better than the Porsche Cayman R's 108-foot braking distance. (That same 335i also stopped from 60 mph in 108 feet.)

Unlike the Cayman, the Mercedes provides an incredibly roomy cabin, with plenty of functionality to go along with performance at the track. Cargo volume is 93.8 cubic feet behind the first row, and the third row folds flat by pushing two rocker switches. That makes it easy to reconfigure the interior to prioritize carrying people over gear, and vice versa.

The interior is quite nice, as you would expect in a Mercedes-Benz. Porcelain white leather with black stitching and Piano Black accents throughout the interior, plus a Bang & Olufsen sound system, make the three-row cabin a warm, welcoming place to be.

However, people who want an AMG because it looks like an AMG won't make the GL63 their first choice. Inside and out, there aren't a lot of cues that indicate its AMG nature. The leather is beautiful, but it isn't significantly different than in the rest of the GL line. The center stack has a lot in common with other Mercedes on the market. It's a classy setup that is mostly easy to use; the exception is the COMAND navigation system, which takes some time to learn.

There are plenty of reasons the GL is our 2013 Sport/Utility of the Year, including versatility, comfort, capability, variety, and power. But when it comes to the AMG version, we expect there to be notable differences between it and the rest of the Mercedes line. In this case, it felt more like a package added onto the GL than an AMG vehicle engineered from the ground up. When it comes to performance at the track and on the road, it isn't the fastest SUV out there -- the last Grand Cherokee SRT8 we tested got to 60 in 4.6 seconds, and the last Cayenne Turbo did it in 4.3 -- but neither of those vehicles offer the versatility of a third row.

The GL63 is an entertaining vehicle to drive, even if it doesn't differentiate itself as much from the standard GL as other AMGs do from their regular versions. But in exchange, you get a sport/utility vehicle that still offers real towing capacity, plus plenty of room for the driver plus a hockey team. And they can all watch as you shame sports cars off the line when the light turns green.


2013 Mercedes-Benz GL63 AMG
BASE PRICE $117,830
PRICE AS TESTED $128,030
VEHICLE LAYOUT Front-engine, AWD, 7-pass, 4-door SUV
ENGINE 5.5L/550-hp/560-lb-ft DOHC 32-valve V-8
TRANSMISSION 7-speed automatic
CURB WEIGHT (F/R DIST) 5787 lb (52/48%)
WHEELBASE 121.1 in
LENGTH x WIDTH x HEIGHT 202.6 x 84.3 x 72.8 in
0-60 MPH 4.7 sec
QUARTER MILE 13.1 sec @ 108.3 mph
BRAKING, 60-0 MPH 104 ft
LATERAL ACCELERATION 0.86 g (avg)
MT FIGURE EIGHT 26.8 sec @ 0.69 g (avg)
EPA CITY/HWY FUEL ECON 13/17 mpg
ENERGY CONS., CITY/HWY 259/198 kW-hrs/100 miles
CO2 EMISSIONS 1.33 lb/mile