Mazda today took the wraps off its second-generation Mazda6 for North America. The production version looks identical to the previously shown spy shots. The car, due to go on sale this summer, grows in every key dimension and features larger engines as well. Mazda says the bump in displacement, as well as handling traits and interior comfort, were "optimized" for North American roads.

Engines will include a new 2.5 liter inline-four and the corporate 3.7 liter V6 borrowed from the CX-9 SUV assembly line. No official numbers have been released but in the European and Japanese Atenza equivalent, the 2.5L makes 167 horsepower, while the CX-9-sourced V6 is good for 273hp. Transmissions for the four-cylinder model will include a six-speed manual or a five-speed automatic. The V6, sadly, will put power down exclusively via a six-speed automatic.

Despite the fastback roofline, the North American 6 will come as a four-door sedan only and Mazda does not mention any other body styles including coupe or convertible models. Just like the original 6, the car will be produced at the AutoAlliance International plant shared with Ford in Flat Rock, Michigan.

The U.S. spec Mazda6 differs from the car previously introduced with a very different look in the rear. Different taillights set them apart, as does the location change of the third brake-light. The license plate moves up in the U.S. version, exhaust tips look sportier and the Mazda emblem shrinks slightly. Look closely and you see even more changes with the rear fascia.

The new 6 is lighter, slightly bigger and more fuel-efficient than the model it replaces. It is believed to be powered by a 3.5 liter V6, although official details have not yet been released.

Expectations are high for the new Mazda6 — the first model almost single-handedly reinvented Mazda and was the fastest vehicle the automaker ever produced to exceed 1 million units sold worldwide.