The xDrive35i's 3.0-liter turbocharged in-line six-cylinder engine is rated at 300 horsepower and 300 pound-feet of torque. It feels like it offers every bit of that to the driver, with good low-end torque and strong acceleration at almost any speed. The eight-speed automatic transmission, common to all X5s, feels sporty enough to keep up with the X5 when the driver wants to hustle, and is very laid-back and smooth-shifting when the pace is more relaxed.
With the xDrive50i, the X5 steps into the realm of the real performance SUV, bringing 400 horsepower and 400 pound-feet of torque from its 4.4-liter twin-turbocharged V-8 engine. The result is something like a very tall performance wagon, with shockingly good cargo room.
The optional AdaptiveDrive dynamic damping system improves the sporty side of the X5. Electronic stability and traction controls provide a safety net that allows a fair amount of fun before slowing things down and straightening them out.
The X5 M also gets a turbocharged V-8 engine, but scores a huge 555 horsepower and 486 pound-feet of torque, delivering sports car-like acceleration. The suspension, wheels, and tires are also upgraded, enabling incredible feats, though to truly tap the X5 M's capability, you have to get to a track. Even the brakes on the 5,250-pound beast are impressive. M Dynamic Mode stability control allows even greater slip angles while still providing computer-aided chassis control.
Off-road, the X5 is perhaps less impressive than some of the alternatives, and the often low-profile tires fitted may compromise grip and rugged-terrain capability, but it's not just a soft-roader. The X5 can handle mud, snow, gravel, inclines, and even water crossings when driven properly.