Forget the clunky name. It doesn't do the X5 with BMW's new-generation, 50-state-legal diesel engine on-board justice. Far removed from the smelly, noisy, American stereotype, the engine serves as an excellent ambassador to the U.S., offering a glimpse at the available civility of the powerful -- and fuel-efficient -- diesels coming ashore lately.

During our recent test of the 2009 BMW X5 xDrive 35d, we found BMW's 3.0L turbodiesel straight six (also available for the 3 Series) smooth, quiet, and potent. The last should come as no surprise, but most consider the other two concepts alien in good-old-fashioned oil burners. Though the engine produces a stunning 425 lb-ft of torque at just 1750 rpm, the forward surge doesn't feel dramatic. It's progressive, but nonetheless quick. At 6.7 sec from 0-to-60 mph, Civic Si owners should think twice before trying to out-accelerate this 5111-lb SUV from a stoplight. X5 owners shouldn't feel too cocky though, as they'll have to keep an eye out for lead-footed Lexus RX 450h drivers; the hybrid RX we recently tested will hit 60 mph a couple ticks faster.

The situation changes when the road bends -- at least in the case of the Lexus. The RX 450h is unable to muster the same grip, falling over a second and a handful of lateral g short of the X5's 27.5-sec and 0.62g MT figure-eight result. But here the Civic zooms away, as it bests the BMW by 1.0 sec and 0.3 g. While the X5's 2.5-ton mass relegates its figure-eight performance in between the Mazda3 and Acura TSX, with a weight distribution of 51/49, it is better balanced than both.

The X5's handling prowess becomes evident behind the wheel. "Minimal body roll, quick turn-in, taut suspension, organic steering -- confronted with a twisty road, this is the hands-down SUV to have," says senior editor Ron Kiino.

On the freeway, the diesel X5's ride is both pleasant and quiet, and the engine barely produces any noise. Press the pedal to overtake, though and the engine note invades the cabin. "From inside, it almost has the same rumble and growl as a big V-8," says veteran test driver Mark Williams. Not nearly the same, however, is the diesel's fuel economy. The EPA rates the xDrive 35d at 19/26 mpg, that's 4 city and 5 highway mpg better than the X5's base gas-powered I-6 offering.

We often hear tall tales of European diesels, stories of ridiculous fuel economy, supercar acceleration, and unmatched utility. While the truth isn't quite so dramatic, as often the case, it's not far from reality. No, the BMW X5 xDrive 35d is not the material of legends (the packaging constraints, limited off-road capability and $65,620 as-tested price don't help), but its smoothness, traceability, and power leave a welcome lasting impression. Just never mind the convoluted name.