We're still not sure why, but high-horsepower, performance-tuned SUVs are fun to drive. They're not as fast as their lower-slung car counterparts, and they're not as useful as their softer-sprung off-road cousins. But the love of cars doesn't always need a reason, and that's why they make vehicles like the 2011 Mercedes-Benz ML63 AMG. Updated only visually for 2011, the new ML63 AMG gets a face that fits more closely with its updated family while retaining its 510-horsepower 6.3-liter V-8 engine. That's still enough to scoot to 60 mph in five seconds flat, and on to the electronically-limited top speed of 155 mph. Shifting is still handled by the AMG Speedshift 7G-Tronic automatic transmission, and all-wheel drive is still split 40:60 front to rear. So what's new for 2011? A new hood with "power domes," darkened bi-xenon headlights, and clear-lens and darkened LED tail lights. Yep, that's a pretty minor facelift.

Off the highway, we were faced with a challenging mountain road through the Los Padres National Forest (coincidentally the same route we drove in the Lexus LFA). We firmed up the suspension and pushed the 5,000-pound SUV hard just to see what it would do. The ML63 AMG feels every bit a 4.5-second vehicle. The brakes also inspired confidence with their firm pedal and progressive travel. There is a lot of heat to absorb, but numerous hard stops didn't seem to tax them. We did find it easy to summon the ABS (inside rear wheel) when we braked late into a corner, but the stability control was unexpectedly unobtrusive. With all-wheel drive, acceleration was brisk but unexciting (sorry, no wheelspin). Throttle application doesn't require much forethought, as there is always grip somewhere. At one point, we unloaded the rear over a rise and mashed the accelerator. For a brief second the rear wheels spun in unison, then they grabbed the pavement and we launched forward (don't ever underestimate 560 pound-feet of torque). And yes, despite its SUV massiveness, the ML63 AMG feels every bit a 4.5-second vehicle. The ML63 AMG has a soft side that completely masks all of its amazing potential. Where the Mercedes-Benz excels is in its ability to execute a near flawless split personality - it is a gentle beauty and monstrous beast.

ML 63 AMG PERFORMANCE PACK! Most SUVs can promise a quiet interior and a smooth ride, but try and find one that can claim a 174-mph top speed on the autobahn or deliver up enough low-end torque to shame a Chevy pickup. With a 7,200-pound tow rating, the M-Class can actually carry its own weight and then some. Source: Strong and fuel-efficient diesel V6; seriously quick turbocharged V8s; serene ride; rich interior trim; roomy backseat; short braking distances. Every element of the 2014 M-Class cabin is thoughtfully engineered and elegantly crafted to make you feel at home, and in control, on any road. The standard 19-inch alloy wheels further accent the already stark design of the M-Class. Sleek and purposeful, the roof rails accommodate a variety of available accessory attachments for carrying bikes, surfboards, skis, snowboards and cargo carriers. Bright white LED Daytime Running Lamps help increase the visibility of your vehicle to oncoming traffic by illuminating front lights whenever the car is switched on. On the inside, wood trim adorns the console, dash, steering wheel and doors.

The standard 4-spoke multifunction steering wheel is wrapped in supple Premium leather. MB-Tex upholstery offers a rich appearance and supple leather-like feel, even in cold weather. Electrically heated front seats quickly take the chill out of even the coldest day. 60/40 split-folding rear seat backs with flip-forward seat cushions allow for a truly flat cargo floor. The Cockpit Management and Data (COMAND) system features a high-resolution color-LCD display. This is utilized to manage audio, video, and other hands free calling and navigation functions. The M-Class features various engines, available at different packages, to suit your needs. The 7-speed automatic has been made even smoother, more responsive and more efficient. Paddle shifters allow you to manually upshift and downshift with just a flick of your fingers. Powerful 4-wheel disc brakes grant you the all of the stopping power that you need. Mercedes-Benz is concerned with keeping the family safe, and the quality of the safety options present on the M-Class is proof of that.