Since its introduction three years ago, the Mercedes-Benz GLK350 has been one of our favorite compact luxury crossovers. It brings much of the Mercedes promise -- rock-solid construction, a sophisticated ride and ample safety features -- to this growing vehicle segment. Now adding to its appeal, the 2013 Mercedes-Benz GLK arrives with thorough updates outside, inside and under the hood.

The GLK's squared-off design aesthetic remains, but the front end now exhibits more slope and visual ornamentation. The differences seem minor at first, but when you park a vintage 2012 next to a 2013, the outgoing model suddenly looks plain by comparison. Once you climb inside the cabin, you sense a similar change. The stark, Germanic environment feels warmer thanks to upgraded materials and a swath of rich wood trim, even though the layout hasn't really changed aside from a slight change in the location of the shift lever and turn signal stalk.

Turning the electronic key in the ignition (still no push-button start here) brings to life a heavily revised V6 engine. It still displaces 3.5 liters, but direct fuel injection and other improvements push output to 302 horsepower and 273 pound-feet of torque. The difference is noticeable, and the V6-equipped GLK350 is now one of the quickest compact luxury crossover SUVs out there. The Audi Q5 and BMW X3 can be equally swift, but there's no denying the new power from the GLK's revised V6 is a major upgrade.

Should fuel economy be more important to you than taking off from traffic lights with vigor, then take note that improved engine efficiencies and one of the best automatic stop-start systems on the market boost the GLK350's fuel economy. If mpg is your priority, though, the new GLK250 Bluetec model deserves serious consideration. The GLK is the first compact luxury crossover to offer a diesel engine option, and the refined and silent new 2.1-liter four-cylinder diesel combines genuinely satisfying performance with segment-topping fuel economy.

The GLK also benefits from high-tech features first found on pricier Benzes. Adaptive cruise control automatically slows the GLK to match the speed of minivans clogging the lane ahead. A gentle buzz in the steering wheel from a lane-departure warning system lets you know if you veer too close to the line, while Benz's Attention Assist stands by in case you fall asleep or simply stop paying attention. There's also now an automatic parallel parking system.

Much improved from last year, the 2013 Mercedes-Benz GLK-Class feels a little more luxurious and special. Of course, nothing has been done to enlarge the backseat and cargo area, however, which remain smaller than most competitors. That's why families might consider the more spacious Audi Q5, BMW X3 and Volvo XC60. Yet for those who are single or whose kids have left the nest (or not yet arrived in it), the GLK is now an even more appealing choice.

The 2013 Mercedes-Benz GLK-Class lineup consists of the GLK350 and the diesel-powered GLK250 Bluetec.

Standard equipment on both models includes 19-inch wheels, automatic headlights, LED running lights, foglamps, rear privacy glass, roof rails, cruise control, dual-zone automatic climate control, eight-way power front seats, MB-Tex premium vinyl upholstery, a leather-wrapped tilt-and-telescoping steering wheel and a cargo cover. Standard electronics features include Bluetooth phone connectivity, the COMAND electronics interface, the mbrace2 emergency communications system and a six-speaker sound system with a CD player and an auxiliary audio jack.

The Premium 1 package adds a power liftgate, auto-dimming mirrors, a panoramic sunroof, four-way driver lumbar adjustment, driver memory functions, a power-adjustable steering wheel, a 115-volt power outlet, satellite radio and an iPod/USB audio interface. The Full Leather Seating package adds leather upholstery, front passenger memory functions, upgraded head restraints and interior ambient lighting. The Lighting package adds adaptive bi-xenon headlights with automatic high beams and washers.

Adding the Multimedia package gets you a rearview camera, a navigation system and voice controls. The Lane Tracking package adds a blind-spot warning system and a lane-departure warning system. More safety equipment is found in the Driver Assistance package, which adds adaptive cruise control and enhanced versions of the blind-spot and lane-departure warning systems that take evasive action if the driver fails to do so.

The AMG Styling package adds 20-inch AMG wheels (19-inch wheels for the GLK250) and aluminum roof rails along with unique LED running lamps and styling elements. The Appearance package adds the aluminum roof rails and different 20-inch wheels (19s on the GLK250).

Stand-alone options include an automated parking system, keyless ignition/entry, the panoramic sunroof, heated front seats, a dual-screen rear seat entertainment system, satellite radio, the iPod/USB audio interface and a premium Harman Kardon sound system.

The 2013 Mercedes-Benz GLK-Class comes standard with a seven-speed automatic transmission. The GLK350 has standard rear-wheel drive, and 4Matic all-wheel drive is an option. All-wheel drive is standard on the GLK250 Bluetec.

The GLK350 is powered by a 3.5-liter V6 that produces 302 hp and 273 lb-ft of torque. An automatic stop-start system shuts down the engine when the car comes to a stop to save fuel. In Edmunds testing, a GLK350 4Matic went from zero to 60 mph in 5.9 seconds, making it just as quick as the six-cylinder versions of the Audi Q5 and BMW X3. EPA-estimated fuel economy is 19 mpg city/24 mpg highway and 21 mpg combined with 4Matic (19/25/21 on rear-wheel-drive models). That's also on par with its Audi and BMW rivals.

The GLK250 Bluetec gets a turbocharged 2.1-liter four-cylinder diesel engine good for 200 hp and a V8-like 369 lb-ft of torque. Mercedes estimates it'll hit 60 mph in 7.9 seconds, which isn't exactly slow but is certainly off the rapid pace set by the GLK350. On the upside, the GLK250 Bluetec is one of the most fuel-efficient luxury crossovers out there, with EPA ratings of 24 mpg city/33 mpg highway and 28 combined. These figures surpass Audi's more costly Q5 hybrid and aren't much lower than the Lexus RX 450h's ratings.

The 2013 Mercedes-Benz GLK-Class comes standard with antilock brakes, stability control and traction control, active front head restraints, front side airbags, front pelvic airbags, full-length side curtain airbags, a driver knee airbag and a driver drowsiness monitor. The new-for-2013 mbrace2 emergency communications system provides automatic crash notification, on-demand roadside assistance and a system that alerts the owner when a pre-selected speed or boundary is exceeded by another driver (say, a teen or valet). Blind-spot monitoring and lane-departure warning systems are optional.

In crash testing, last year's GLK received the highest possible rating of "Good" in the frontal-offset, side and roof strength tests from the Insurance Institute for Highway Safety.

In Edmunds brake testing, the GLK350 4Matic came to a stop from 60 mph in 117 feet, a short distance for this class.

The 2013 Mercedes-Benz GLK's most notable characteristic is its rock-solid feel over every bump and road imperfection. Even the worst potholes and railroad tracks pass with a muted thump. The well-damped ride might be too firm for some people, but the GLK-Class is otherwise a well-tuned luxury vehicle that glides along freeways with comfort. And while not overtly sporty, the GLK still inspires confidence around corners with revised steering for 2013 (electric-assist versus hydraulic) that transfers a decent amount of feedback with a well-weighted feel.

The V6 engine is one of the GLK350's strong suits, delivering vigorous acceleration and better fuel economy than before. The new automatic engine stop-start system operates seamlessly and limits the obtrusive noise and vibration associated with these increasingly common systems. The seven-speed automatic transmission can still be slow to downshift in its default setting, but selecting Sport mode sharpens up things considerably.

Meanwhile, the newly added four-cylinder diesel in the 2013 Mercedes-Benz GLK250 Bluetec is a treat of a different sort. The brawny torque for which diesels are renowned is put to good use, as the GLK250 Bluetec pulls away from slower traffic with surprising ease, even in freeway passing situations. The diesel-engine GLK doesn't launch from stoplights with the same vigor as the V6 version, but not everyone lives for V6 punch. If that's you, you'll discover the diesel engine's startling refinement and fuel economy pay-off are a more than acceptable trade in the GLK.

The 2013 Mercedes-Benz GLK-Class has a much classier, richer-feeling cabin than before, largely thanks to the curved plank of wood that stretches across the dash. What haven't changed are the GLK's top-notch materials, tight panel fits and precise build quality. Some shoppers might lament that leather upholstery isn't standard equipment, but the standard MB-Tex upholstery (technically vinyl) actually breathes better than leather, wears better over time and your friends will never be able to tell the difference. Plus, no cows were harmed in the making of your Mercedes -- well, except for the leather used to trim the steering wheel and shift lever.

Cabin controls are a little complicated at first, but the combination of dashboard buttons, steering wheel controls and the multifunction COMAND knob provide a reasonable solution for the operation of the complicated stereo, navigation and telephone functions. The climate controls are simple to use, but are mounted a little low in the GLK.

Maximum cargo capacity is 54.7 cubic feet, which is less than every compact and midsize competitor (often considerably so). The same goes for backseat room, making the GLK-Class a better choice for singles or couples without kids rather than families. Headroom is ample for all passengers.