At the time, the Porsche 997-generation 911 GT2 was the most powerful and fastest road-going 911 ever to have been sold to the public. The GT2's engine was based on the existing 3.6 L (220 cu in) flat-6 engine, but features twin variable geometry turbochargers (as used on the 997 Turbo), generating a maximum power output 523 hp, mated to a 6-speed manual transmission. Like its predecessor, the 996 GT2, the 997 GT2 uses a rear wheel drive layout for reduced weight primarily for competing in GT2 class racing. It was succeeded by the 997 GT2 RS in 2010.