BMW’s X6 is a sport-utility vehicle that, like its competitor, the Infiniti FX, puts the emphasis on sport rather than utility. But to a greater degree than the FX, the X6 sacrifices utility for style.

The X6’s swoopy shape is striking, making the vehicle look smaller than it is. But step closer and its mammoth tires, elevated ride height and beefy shape reveal the vehicle’s true size.

The roofline tells you what you need to know about the X6’s utility: It has little.

It seats four, but the two passengers in the rear must battle a low seat cushion and sloping roof. The cargo compartment holds 25 cubic feet unless you fold the rear seats down.

Even then, the sloping roof limits the height of any cargo you might carry.

So if the X6 won’t hold a lot of people or stuff, what it’s good for?

Well, it goes like the dickens, thanks to a pair of brilliantly engineered twin-turbocharged engines. The xDrive35i has a 300 horsepower, 3.0-liter inline six-cylinder engine and starts at $56,325. The xDrive50i has a 400-horsepower, 4.4-liter V-8 engine and starts at $67,025.

The vehicle I tested, an xDrive50i, was a 2008 model, but it is essentially the same as the 2009 model, which sees a price increase and the availability of a few new options, such as rear heated seats.

Power flows to all four wheels through a system BMW calls “Dynamic Performance Control.” Not only does that allow power to go to all wheels, but it also lets torque be directed to a specific rear wheel, which BMW says enhances steering precision and handling.

It’s hard to argue with the results. The X6 feels as agile as the X5, with which it shares its underpinnings.

But there are differences. The X5 is lighter, and the X6’s extra weight is noticeable despite its speed. Also, rear visibility is severely restricted, and rearview camera would be helpful.

The ride is typical of a BMW: firm but absorbent.

To say acceleration is brisk is like saying that the economy is suffering from a slight downturn. The six-speed automatic is fiercely responsive and always seems to be ready to party. For those who must be in command, the steering wheel has standard paddle shifters, which enable the driver to manually shift gears.

Meanwhile, the outstanding brake system, along with the usual host of electronic nannies, is there to rescue you if you get in over your head.

The instrument panel will look familiar to any BMW aficionado. Features include BMW’s iDrive system, which uses a large mouse-like knob to control audio, navigation and communications functions. Yes, it’s fussy. Yes, you get used to it. No, I don’t like it.

The X6 has the dynamic thrust and eagerness of a true BMW, but will it find a buyer? Other trucks — such as the Range Rover Sport and the Infiniti FX — are tuned more for the highway than the hinterlands, but both seem more practical than the X6. Besides, BMW already offers the X5, an agile, willing SUV.

That makes the X6 kind of a head-scratcher. Who is this built for?

If you need utility, buy an X5. If you want some utility along with car-like handling, buy a 5-Series wagon.

But if you don’t cart around more than four people or a lot of stuff and you desire speed with a bit of agility and a look that stands apart from the crowd, the X6 is your ride.BMW X6

Pro: Typical BMW strengths

Con: Compromised utility

Stats

Engine: 4.4-liter DOHC V-8

Wheelbase: 115.5 inches

Length: 192 inches

Weight: 5,269 pounds

Cargo space: 59.7 cubic feet

EPA rating (city/highway): 13/18 mpg

Fuel economy: 17 mpg

Fuel type: Premium unleaded

Base price: $63,000

As tested: $75,120