Spotted in Europe during winter testing, this lightly camouflaged G-Class (seen here alongside its G 55 brother) has a heavily-vented front bumper that is our only substantial clue as to what lies under its angular bonnet.
Some say it's powered by the 6.2 litre naturally-aspirated AMG V8 that's currently being phased out by Mercedes, but we're not so sure.
Behind the prototype's cheek vents appear to be a pair of intercoolers, things that wouldn't be needed on a naturally-aspirated engine like the AMG 6.2.
AMG's new twin-turbo 5.5 litre M157 V8 is also another possiblity, but with Mercedes tuner Brabus having already shoehorned a V12 into a G-Class, we're betting Mercedes will opt for the already-proven V12 conversion.
As far as power and torque goes, the biturbo V12 produces as much as 500kW and 1000Nm in SL 65 trim - certainly more than enough to fry the G-Wagen's tyres. Even if it's the smaller 5.5 litre biturbo V8, you can still expect a mammoth 450kW and 800Nm.