RICHARD BLACKBURN June 23, 2012
The term sports utility vehicle is largely a misnomer.
SUVs are typically about as graceful as a baby elephant and weigh as much as a fully grown one.
These two are a bit different, though. They may look like off-roaders but they're really more like sports cars on stilts.
They come from the performance arms of BMW and Mercedes-Benz. The X5 M is fettled by the company's fabled M division, while the ML63 is tuned by AMG.
They may have different badges but they subscribe to the same theory: that too much is never enough. Between them, they have four turbos, more than 800kW of power, eight exhaust pipes and almost five tonnes of metal.
Each car is capable of reaching 100km/h in less than five seconds and both have massive brakes to arrest their progress with indecent haste.
If you're planning a road trip to Nimbin, or towing a Greenpeace dinghy, you'd leave this pair at home. The BMW officially uses 13.9 litres of fuel per 100 kilometres, more than four times the consumption of a Toyota Prius. The Mercedes-Benz is marginally better at 11.8L/100km, thanks mainly to stop-start technology.
To the average punter, it's a severe case of overkill. So why do people buy them?
We took the pair down to the Marulan Driver Training Centre in the NSW Southern Tablelands to try to unravel their charms in an environment of high-speed corners and no speed limits.
The X5 M is a bit of a wolf in sheep's clothing. From the outside it doesn't look remarkably different from a garden-variety X5, except for a front bumper design that has bigger air-intake vents, a lower front lip and a honeycomb mesh pattern in the grille. There's also a subtle badge on the flanks, blue brake calipers, and 20-inch low-profile tyres.
Inside there are M badges on the sills and in the instrument panel but aside from a chunky sports steering wheel with paddles and blue-and-red stitching on the rim, the cabin doesn't scream sports car. In fact, it is disappointingly similar to cheaper models.
What's not disappointing, though, is the equipment crammed into the car. Standard gear includes a television tuner, satellite navigation, heated seats, a head-up speedo display, a big sunroof and a powered tailgate.
There's also plenty of technology at work beneath the surface. The "adaptive drive" system is designed to reduce leaning through corners and make the steering sharper. It can be set to either comfort or sport modes. The torque can be split differently among the wheels to help drive out of corners and engine parameters can also be changed.
On the track, the level of engineering that has gone into the X5 M becomes obvious. This is a car that belies its weight and height, changing direction like a sports sedan and offering phenomenal grip and confidence-inspiring poise through corners.
The steering is sharp and accurate but never twitchy, while the car settles quickly over bigger bumps and remains firmly planted even under hard braking.
Unfortunately the car isn't as impressive once you leave the marble-smooth confines of a racetrack. The suspension fidgets over concrete joins and corrugations and suspension noise can be quite noticeable in the cabin.
The 4.4-litre engine, which puts out 408kW and 680Nm of torque, moves the X5's considerable frame rapidly after some initial hesitation as the twin turbos spool up. The exhaust note is purposeful but lacks the aural drama of many V8s.
It's a subdued grumble rather than a menacing snarl. BMW claims a 0-100km/h time of 4.7 seconds and our wet-weather results showed a reasonable 5.5 seconds with a full tank of fuel.
The BMW's front seats are supportive and comfortable, while in the back there's plenty of legroom and headroom.
In short, it has all the comforts of a family hauler with the performance of a V8 sedan: a pretty compelling proposition.
In standard form, the Benz's 5.5-litre twin-turbo puts out slightly less power (386kW) but more torque (700Nm) than the BMW.
Our test car came with the AMG Performance package, which pumps the numbers out to 410kW and 760Nm and costs another $10,800.
The extra spend also gets you a racy leather and suede flat-bottomed steering wheel, big red brake calipers, a roof spoiler and a carbon-fibre engine cover.
The additional power and torque trims the official 0-100km/h time by only 0.1 seconds to 4.7 seconds but, in our track tests, the Mercedes felt noticeably stronger than the BMW off the mark and churned out a 5.1-second 0-100km/h sprint.
The extra performance is backed up by a feral soundtrack that wouldn't be out of place on a racetrack.
The euphoria only lasts until the first corner, though, where the Benz doesn't have the cornering smarts to keep up with the BMW. There's more body roll, a spongier brake pedal and a tendency to push the nose wide through corners, then snap the tail out when exiting. In short, it's fun but it's more of a handful, especially on the damp track we tested it on.
So the Mercedes has the grunt and growl, the BMW the poise and agility. In the end that leaves the cabin ambience and the features list to settle the argument.
The minute you climb into the Mercedes, it feels more special than the X5. It starts with the backlit AMG moniker on the door sills and continues with the quality stitched leather inserts in the door, the sporty alloy pedals and the embossed logos on the seat backs.
The display in the centre console is higher resolution and includes thoughtful touches such as displaying album covers when you hook up an iPod. The instrument panel also makes the BMW look plain, with more information presented in a much classier way. While the X5 bears too close a resemblance to cheaper, smaller BMWs, the ML feels like it belongs in the same stable as the S-Class limousine.
The list of goodies in the cabin includes a sunroof, a Harman Kardon audio system, television tuner, heated and ventilated front seats, Bluetooth and internet connectivity.
Driving aids include a reversing camera, air suspension and active dampers, active anti-roll bars for flatter cornering, a race timer, blind-spot and lane-departure warning and active cruise control. You can also choose a sport setting for more aggressive gear shifting.
If you want an SUV that has a pretty good crack at defying physics, then the BMW is the choice. If you're more interested in something that combines genuine luxury with the biggest and loudest donk in town, then it's the Mercedes.
The BMW may have won the battle of Marulan but the Mercedes wins the war because it's the more complete package for the other 364 days of the year.
BMW X5 M
Price From $183,200
Engine 4.4-litre twin-turbo V8
0-100km/h 4.7 secs; our time 5.5 secs
Mercedes-Benz ML63 AMG
Price From $177,900 (as tested $188,700)
Engine 5.5-litre twin-turbo V8
Transmission 7-sp auto
Power 386kW/700Nm (as tested with performance pack 410kW/760Nm)
0-100km/h 4.8 secs (4.7 secs with performance pack); our time 5.1 secs
Porsche Cayenne Turbo
Powered by a 4.8-litre turbo, the Porsche puts out 368kW and 700Nm, achieving a claimed 0-100km/h time of 4.7 seconds. Fuel consumption is 11.5L/100km. It rivals the BMW for car-like driving dynamics but ought to: it costs $248,600.
Audi Q7 6.0 TDI
Huge 6.0-litre V12 diesel matches the other Germans for power, with 368kW, but blows them to the weeds with 1000Nm of torque. Only good for a
0-100km/h sprint of 5.5 seconds and uses almost as much fuel, at 11.3L/100km. Not as agile as others. Costs $257,700.
Range Rover Sport
The Rangie's supercharged 5.0-litre V8 puts out 375kW and 625Nm but is quite a bit slower, with a 0-100km/h claim of 6.2 seconds. Thirsty (14.9L/100km) and cumbersome in the bends but makes up for it with a beautiful interior and genuine off-road ability. A bargain in this company at $161,400.