A pair of Mercedes-Benz G-Class test mules has been spotted once again by our spy photographer conducting winter tests in Sweden. Though the SUVs don't look that different from when we saw them last, still sporting the minor facelift, one of them could be the rumored V-12-powered G65 AMG.

The test mules retain the classic, utilitarian shape of the G-Class, and still sport the updated grille, new side mirrors, and revised front bumper that we saw last time around. The dual side-exit exhaust pipes are also present, placed in their usual spot right in front of the rear wheel wells. One interesting difference about these mules, however, is the appearance of openings in the front bumper, which our spy photographer believes hide turbocharger intercoolers. One test mule sports a single intake vent on the passenger side of the front bumper, while its otherwise identical testing partner sports two. Our spy photographer speculates that the one with the single opening is packing Mercedes' 5.4-liter twin-turbo V-8, estimated to make around 525 hp in the G55 AMG. The other one could be hiding the S65 AMG's twin-turbo 6.0-liter V-12 under its hood, good for around 612 hp. If MB's current naming scheme sticks, that would make this SUV a G65 AMG.

Further evidence that this one is the more powerful of the two can be seen in the brakes, which look upgraded for better stopping power. It's believed that the V-12-powered G-Class will be a limited-run vehicle, with production numbers as low as 200 units at 250,000 euros (roughly $326,850) a pop. Mercedes-Benz won't confirm the existence of either vehicle, though rumor has it that these hot boxes could debut as early as the Detroit show in January. Whatever beastly powerplants Mercedes has in store for these rugged machines, we're glad to see the automaker hasn't given up on its tried-and-true G-Wagen just yet.

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