The 2013 Cadillac ATS, which we first saw at the Detroit auto show, will start at $33,990 when it goes on sale this summer, General Motors said on Monday. The range-topping version will carry a price of $42,090. Power for the base model will come from a 2.5-liter, four-cylinder engine that returns 30 mpg on the highway. A mid-level model will offer a 2.0-liter turbocharged four and will be available with rear- or all-wheel drive. Cadillac's 3.6-liter V6 will power the top model, with an estimated 320 hp.