If there was ever an SUV that wanted to be a sport sedan, it's the BMW X5. And now that the second-generation X5 has a 350-horsepower, 4.8-liter V-8 and revised high-tech suspension, it may be one step closer to its goal.

The roads winding through the foothills north of BMW's South Carolina assembly plant are the perfect place to stretch the X5's legs. It hustles effortlessly over the twisties, with surprising amounts of grip, absorbing hidden bumps (although biased on the stiff side), braking with confidence, and accelerating with impressive authority for a weighty 5335-pound vehicle. On switchbacks, the lack of head toss is almost surprising, but can be attributed in large part to newly developed computer-controlled shocks and a stiffened chassis. The engineers broke with BMW tradition, opting for a control-arm front suspension rather than the usual MacPherson struts.

This newfound dexterity is in spite of the fact that the X5 has grown in length, width, height, and weight. But the X5 didn't get bigger simply for the sake of getting bigger; BMW added an optional third row of seats to give drivers the ability to carry seven passengers, as long as the two relegated to the third row are pint-size youngsters. Also, the second-row seat, split 60/40, flips forward to provide access to the third row, but kids likely will find it easier to scramble over the top of the second row.

Horsepower went up in the base 3.0-liter I-6 and the optional 4.8-liter V-8. This particular inline-six is an entirely new engine for the X5, though it has already been seen in the 3 Series. It uses a combination magnesium/aluminum block for lighter weight and produces 260 horsepower, compared with 225 for the old I-6. The new 4.8-liter V-8 is a larger displacement version of the previous 4.4-liter V-8, increasing horsepower from 315 to 350. Both engines feature BMW's Valvetronic variable intake and valve lift system, contributing to improved power and fuel efficiency, and are backed by a six-speed automatic (the six-speed manual is no longer available).

The X5's styling is substantially modernized throughout, for a much-needed update without the extravagant flourishes seen on some of the other models. While earlier versions of iDrive have been criticized as difficult to navigate, the new version is much easier to use, especially with its large video screen.