This isn't a truck anymore. The all-new 2006 Mercedes-Benz M-Class is unibody, not body-on-frame like the 1998-2005 model. But that doesn't matter--most people who care about the structure didn't mistake the previous M-Class as a serious off-roader. This is one of the pioneers of the luxury crossover segment, an SUV designed to safely transport you to and from your suburb, through virtually any weather Mother Nature can serve up.

With the pretentions gone, the second-generation M-Class, the W164 (German car nuts love those alpha-numeric codenames) washes away memories of W163, the first generation. The M-Class's new image is less off-roader and more luxury-transportation module that can handle adverse conditions in optimum comfort for four adults (and one kid). It's as much an oversize prestige sedan as it is a sport/utility, with the tall ride height and easy step-in that the market demands.

The W163 broke ground as a luxury crossover vehicle and quickly hurt itself with early quality issues. The first M was too short on luxury for a Mercedes and didn't have the ride, handling, and refinement expected from a luxury crossover. So the W164 M-Class is new from the ground up. Its optional 5.0-liter V-8 is the only major component that carries over from the prior model, with power upped from 288 horses to 302, making way for the new V-6, with its 46-horse gain over the old 3.7-liter 18-valve. Mercedes figures the ML500 will account for 25 to 30 percent of M-Class sales, with the rest going to the ML350 and its excellent 268-horsepower, 24-valve, 3.5-liter V-6. Both engines come standard with a seven-speed automatic that has you in third gear before you get across an intersection. Its gearshift is an electronic control on the steering column, making room for two big cupholders in the console.

As for the switch from a "truck" frame, these were never meant to be trail machines, and the new model, available again only with all-wheel drive, is now without the two-speed transfer case, contributing to a 200-pound weight savings in the ML350 and ML500. Still, they're much more capable on bad roads than most people need. A hill-descent control uses ABS sensors and the seven-speed autobox to keep the miles per hour in the single digits on steep downhill runs. The optional Airmatic height-adjustable air suspension raises the body for an extra three inches of ground clearance, up to 77 mph. If you plan to do any dirt driving at all, you'll want to order this option, because the M-Class is also longer, lower, and wider than the truck it replaces. In the 2007 model year, you can recover that 200 pounds by ordering an off-road package, which includes two locking differentials, a two-speed transfer case, and the Airmatic package.