Cadillac's ATS could prove to be one of 2012's most important cars, particularly for General Motors.

Going head-to-head with the BMW 3-Series and Mercedes-Benz C-Class, the ATS will need to perform at stratospheric levels in all disciplines to match the talents of the German duo.

It will also need to be economical, and GM President Mark Reuss has confirmed that a diesel-engined variant of the ATS will appear within its first lifecycle. The news was revealed on Twitter by GM's product and technology PR, Jason Laird.

Details for the diesel model are slim at the moment, but the engine will join the 270-horsepower four cylinder and 3.6-liter, 318-horsepower V6 in the ATS lineup.

The new diesel will have some tough competition. BMW's current 265-horsepower 335d sedan manages 36 mpg highway, and it's about to be replaced by the new 3-Series, which is both more powerful and more efficient across the range.

The ATS will weigh less than 3,400 pounds and has even 50/50 weight distribution, so this should be one diesel sport sedan that's fun to drive, as well as frugal and fast.

We'll keep you updated on further details, and any other news that emerges from the 2012 Detroit Auto Show. For more information on the 2013 Cadillac ATS, head over to Motor Authority.


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