Even though the standard 2012 Mercedes-Benz M-Class is still undergoing development, the company’s AMG division has began testing the high-performance version of the series.

Expected to arrive shortly after the standard M-Class model, which itself, will go on sale in late 2011, the ML 63 AMG will feature the brand’s newly developed 5.5-liter twin-turbocharged V8 in place of the outgoing car’s naturally aspirated 6.2-liter unit.

AMG has said the 5,461cc bi-turbo V8, which will be used on a variety of Mercedes-Benz models, packs 544-horsepower and 800Nm or 590lb ft in standard form, while a performance pack upgrade will increase those figures to 571HP and 900Nm or 663.8 lb-ft, respectively.

It remains to be seen what kind of numbers the bi-turbocharged V8 will deliver on the new ML 63 AMG.

Along with the new powerhouse, the AMG version of the new ML will feature an upgraded suspension, bigger and more powerful brakes, beefier tires and alloy wheels as well as a cosmetic package for both the interior and exterior of the vehicle.