Cadillac is preparing to expand its model line-up for the 2012 year with a new entry in the mid-size saloon segment. Going straight for the BMW 3 Series, Mercedes-Benz C-Class and Audi A4, the new Cadillac is codenamed ATS. All the company has released so far is this sketch, but we know that the smallest vehicle in the carmaker’s range will begin production next summer at the same Michigan assembly plant that already builds the CTS saloon, Coupé and estate. In order to manage juggling this production, the plant has received a $190 million investment and opened up 600 new jobs for the ATS.

Even though nobody in Cadillac is divulging too much information about the ATS, details have been seeping out for a while, so we know it will be rear-wheel drive with optional all-wheel drive. There are also strong possibilities of ATS convertible, coupé, and estate body styles. Technical information is also unavailable, but guesses point at a turbocharged 3.0-litre V6 to compete with BMW’s turbo six-cylinder, as well as the already existent 2.0-litre turbo four-pot to take on the 325i, C250, etc. A hot ATS-V is very likely, powered by a V8 and taking on the Merc C63 AMG and BMW M3. Now we’re talking…