The twin-turbo 3.0-liter inline-six-cylinder that powers the X6 xDrive35i is the same engine that impressed us in the 335i and 135i, and it shows itself to be a capable SUV engine, too.

Even though the six-cylinder uses two turbochargers to make its 300 horsepower and 300 pounds-feet of torque, the engine doesn't display any of the negative characteristics in around-town driving — like power lag — that you might associate with a turbocharged engine; you just get smooth power when you press the gas pedal. Dropping the six-speed automatic transmission into its Sport mode shows off the engine's responsiveness better than regular Drive.

The inline-six should offer plenty of power for most buyers, but BMW also sells a 400-hp X6 xDrive50i. Its 4.4-liter twin-turbo V-8 rockets this big vehicle from zero to 60 mph in 5.3 seconds, according to BMW. You can feel that quickness in everyday driving, as the V-8 moves the X6 with a degree of authority that's surprising for a larger SUV. Even at highway speeds, if you mash the gas pedal the xDrive50i lunges forward with a level of assertiveness you don't see in a lot of vehicles. What's more, the V-8 sounds great whether you're driving around town or slicing through highway traffic. It creates a smooth, deep and powerful sound.

The V-8 pairs with a six-speed automatic. It makes acceptably smooth shifts and quick kickdowns, but where it excels compared to other automatics is in the shift quickness of its clutchless-manual mode, which enhances the appeal of this feature immensely. Clutchless-manuals aren't usually that compelling because many aren't that responsive — you might move the gear selector to change gears then wait a second for it to happen. When you nudge the gear selector in the xDrive50i — to downshift or upshift — the gear change happens nearly instantaneously, and this makes the mode much more enjoyable to use.

Gas mileage for the xDrive35i is 15/20 mpg city/highway; it dips to 13/18 mpg for the xDrive50i.

Toward the end of my time with the X6 xDrive35i, an electrical problem cropped up that nearly brought this SUV to its knees. All of the gauges and displays in the instrument panel went dead and the drivetrain defaulted to a low-power mode in which the SUV could still be driven, but with significantly reduced responsiveness. A BMW dealer was able to bring the X6 back to health, but it was disconcerting to experience a problem this big in a new vehicle.

The X6 comes with vented disc brakes at all four corners that stop this large SUV handily. The brake pedal only needs light pressure to engage the brakes, which are easily controlled.