The M6 will return in 2005, this time with a 5.5-liter V-10 engine pushing nearly 500-horsepower. Sources tell us the all-new M6 will reach 0-60 in under 5.0 seconds. Take a gander at the huge, cross-drilled brake rotors. Major competitors will surely include Porsche's 911 Turbo and the Mercedes-Benz SL55 AMG. An M6 Convertible will debut a year later.