Epsilon is General Motors' mid-size front-wheel drive automobile platform. The architecture was developed by Opel, and debuted in the 2002 Opel Vectra and 2003 Saab 9-3. Since this platform falls squarely in the center of the worldwide automobile market, GM plans to produce a great many Epsilon vehicles with over a dozen variations. As of 2005, it was GM's highest volume worldwide platform.