With many of its competitors planning sleek four-door coupes of their own, Mercedes Benz has decided to update its original CLS sedan, the car that created the segment back in 2004. Similar models from the likes of Porsche, Aston Martin and Jaguar have been confirmed, but it’s also rumored that BMW, Audi and Volkswagen will be releasing the stylish sedans as well.

To combat the competition, Mercedes is adding a few cosmetic changes to the CLS as these disguised test mules reveal. The major change is a revised grille, similar to that seen on the larger CL coupe, while the rear end gets a new taillight design and bumper.

The facelifted CLS is expected to be displayed at September’s Frankfurt Motor Show with the first sales to start in early 2008. Follow the jump to see several images of the CLS mule undergoing cold weather testing in Europe.

[Source: Auto.cz]