Highly capable off-road wagon or the 4WD equivalent of a Gucci handbag; however you view the Mercedes G-Class, the updated model is now available with a grunty 2.9-liter six-cylinder turbo diesel engine that takes you some 20 percent farther per gallon than the gasoline-powered G 500.

The new OM 656 diesel engine in the G 350 D is designed for efficiency, power and a quiet, comfy drive while meeting emissions standards into the future. In the name of efficiency, it recruits variable valve timing, two-stage exhaust turbocharging, a stepped-bowl combustion process and Nanoslide low-friction cylinder coatings.

When you lift your foot off the gas to coast, the 9G-Tronic auto transmission effectively engages the clutch so you're more or less coasting in neutral instead of wasting revs. The result is a combined-cycle NEDC fuel consumption rating of 9.8 to 9.6 l/100km (24 to 24.5 mpg) compared to the G 500's 12.1 to 11.5 l/100km (19.4 to 20.4 mpg).

In addition to catalytic converters and multi-path exhaust gas recirculation, the OM 656 engine also features an Adblue aqueous urea solution that feeds into the exhaust and turns up to 80 percent of the car's nitrous oxide emissions into water and nitrogen. You can fill it up easily at a service station when the Adblue runs low.

Part of the slightly agricultural feel of a diesel motor can make itself apparent at the lights, where they rattle and shake considerably more than the average gasoline motor. To combat this, Mercedes has introduced active engine mounts, which soften off below walking speeds, then firm right up when the engine is revving. What remarkable hoops the auto industry is willing to jump through to mitigate the annoying side effects of combustion engines.

The diesel G will make a reasonably modest 286 hp, but a healthy peak torque of 600 Nm (442.5 lb-ft) that's available between 1,200 and 3,200 rpm.

And we'll leave you with a beautiful nugget from the press release, which claims the new G 350 D is "as powerful and superior as never before." There's a Christmas head-scratcher for you.

View gallery - 8 images