Sigma was General Motors' mid-size rear-wheel drive automobile platform. The architecture debuted in 2002 with the 2003 Cadillac CTS and is adaptable for all-wheel drive and extended wheelbase versions. The long-wheelbase Cadillac STS replaced the front-wheel drive GM G platform Cadillac Seville. The CTS was a replacement for the rear-wheel drive V-body Cadillac Catera. All Sigma vehicles are built at the purpose-built Lansing Grand River factory in Lansing, Michigan. Vehicles based on this platform: