2012 BMW X5 M vs. 2012 Jeep Grand Cherokee SRT8, 2012 Mercedes-Benz ML63 AMG, 2012 Porsche Cayenne Turbo

2012 BMW X5 M vs. 2012 Jeep Grand Cherokee SRT8, 2012 Mercedes-Benz ML63 AMG, 2012 Porsche Cayenne Turbo 2012 BMW X5 M vs. 2012 Jeep Grand Cherokee SRT8, 2012 Mercedes-Benz ML63 AMG, 2012 Porsche Cayenne Turbo
Comparison Tests

Examine the various branches of  the SUV family tree, and none proves more eccentric—nor seemingly as self-defeating—as the luxo-hot-rod limb. Attaching massive horsepower to massive mass produces a massive window sticker and also feels a lot like one of  those futile gestures familiar to overweight opossums and five-foot-tall brigadier generals. In this comparo, the average weight of our participants is 5272 pounds. They produce an average of  519 horsepower. Their average as-tested price is $103,999. Who’d have the nerve to conjure such a vehicle, then express a desire—never mind the cash—to achieve speed in a manner so counterintuitive? It’s like gold-plating the Goodyear blimp. It’s like taking weird Uncle Herb off his meds and giving him six credit cards and the keys to a liquor store.

Of course, it’s life’s guilty pleasures that add zest to the daily grind.  And what vehicle more clearly shouts to the neighbors, “I just slept with your wife!” than a hulking yellow Porsche? But the funny underlying truth is, these vehicles aren’t any crazier than hot-rod wagons—well, maybe a little—and any residual insanity pretty much evaporates the moment you personally unleash 500-some horsepower to slingshot out of an increasing-radius downhill turn in Ohio’s Hocking Hills. It’s like riding a runaway Sherman tank with wings.

We last compared hi-po SUVs in January 2010. Back then, we included a Range Rover Sport Supercharged, but it finished last. So this time around, we ditched the Brit in favor of the new 550-hp Mercedes-Benz ML63, the first of these bruisers to wear an AMG badge since the third-gen MLs were launched in 2011.

Returning to the fray is the Jeep Grand Cherokee SRT8, which finished third in 2010. Since then, the Jeep has benefited from a full redesign including a revised rear suspension, a stiffer body structure, 50 bonus horses, paddle shifters, an improved ride, and a pair of hood-mounted heat extractors that look like dinosaur nostrils. What’s more, the Jeep’s old center-mounted exhausts have been ditched in favor of conventional left/right exits, and a Class IV hitch is now a factory option.

The Porsche Cayenne Turbo returns, too, hoping to improve on its previous runner-up finish. But this is the second-gen Cayenne, with a body that looks less air-puffed from every angle. It rides on 1.6 inches of newfound wheelbase, includes a wholly new cockpit that in several ways mimics the Panamera’s, and makes use of a revised all-wheel-drive system connected to an eight-speed Tiptronic automatic. Cargo room is up and weight is down. Our test car proved 63 pounds lighter than the Turbo S we tested in 2010.

BMW’s X5 M likewise returns, hoping to retain its champion status. It affords us a chance to sample the latest iterations of BMW’s iDrive, full-time all-wheel-drive system, and limited-slip torque-vectoring rear differential. You believe that? Ha-ha. All we really wanted was to mess around again with 555 horsepower, obtaining 60 mph in 4.0 seconds. That’s quicker than an Aston Martin V-12 Vantage. From a 5289-pound SUV with $100 “high-gloss roof rails”—proof that BMW is amused by all of this, too.