For 2010, the high-performance BMW X5 M joins the lineup. The X5 M uses a twin-turbocharged 4.4-liter V8 that makes a whopping 555 horsepower. X5 M comes standard with BMW's xDrive all-wheel-drive system, a stiffer suspension, and sport seats. Exterior cues indicate its performance potential. 

In addition to three gasoline-powered models, BMW offers a diesel-powered model, the X5 xDrive35d, which is as clean as any of its gasoline counterparts. The diesel model improves mileage nearly 25 percent compared to the X5 xDrive30i with its gasoline-powered six-cylinder, yet the diesel accelerates faster and can tow more. 

The BMW X5 emphasizes the sport half of the sport-utility equation, even with the diesel engine. While the current model offers more utility than ever, the X5 comes up short in cargo-passenger flexibility compared to many luxury SUVs. As opposed to hauling acres of equipment and gear, the X5 provides the equipment enthusiast drivers expect when they want to enjoy the art of driving as much as they're able. Just plan to travel fairly light. 

All four BMW X5 engines deliver plenty of usable torque for good acceleration, and the X5 M engine is a beast. The gasoline engines feature turbine-like smoothness. The inline six-cylinder in the xDrive30i delivers the kind of response we expect in a sports sedan, and it shouldn't leave owners pining for the V8s. The 4.8-liter V8 in the xDrive48i simply offers more power for passing and towing. The X5 M version is stunningly fast. No matter what powertrain you choose, you won't be disappointed. 

The X5 is styled in obvious BMW fashion, only taller, with traditional Bimmer cues like the twin-kidney grille and dual-beam headlight clusters. Inside, it offers plenty of room for five, with a nice, rich finish and nearly all the bells and whistles one expects in a high-line luxury sedan. The back seat is more than roomy enough for two adults, three in a pinch, and there's enough cargo space in back for a two-day family outing. The X5 can expand to seven-passenger capacity with an optional third-row seat, but that third seat won't look particularly inviting to anyone asked to ride in it, and it wipes out the cargo space. 

The X5 is not a traditional SUV. BMW shuns the SUV tag entirely, describing the X5 with it own copyrighted label: Sport Activity Vehicle, or SAV. With all seats lowered for maximum cargo capacity, it offers less space than do most competitors, from Acura to Volvo. The gas-powered models aren't class leaders in fuel economy. And sport in the X5 context does not mean off-road capability. While the X5 has some mild off-road prowess, the xDrive all-wheel-drive system was developed for slippery roads and sporty driving rather than sand dunes and rutted hillsides. Indeed, the X5's strength is its ability to get down the road in the step-on-the gas, shove-it-through-corners fashion of a genuine sports sedan. 

The X5 can tow a substantial 6,000 pounds, however, and the all-wheel-drive can be a great friend in a blizzard. Those sound like the credentials of an SUV. 

The X5 gets high marks for safety. It performs well in both government and insurance industry crash tests, and it has been designated one of the Top Safety Picks by the Insurance Institute for Highway Safety. 

In addition to the new X5 M model, 2010 changes to the X5 lineup include some equipment upgrades. Now in its fourth generation, BMW's iDrive control system gets a revised menu interface, an 8.8-inch display screen and an 80-gigabyte hard drive to hold navigation map information and music files. HD radio is now standard and automatic high beam headlights are offered as a stand-alone option. Finally, the rearview camera adds a top view that gives 360-degree vantage when backing up.