General Motors announced yesterday that it will invest $190 million in its Lansing Grand River assembly plant for the production of a new Cadillac model that will fit below the Cadillac CTS and will compete with the likes of the Mercedes-Benz C-Class and BMW 3-Series.Known as the Cadillac ATS, the model is expected to debut in a sedan variant in the fall of 2012 as a 2013 model year. GM doesn’t