Well, summer is here in Chicago, and with it, the latest Mercedes-Benz GLK-Class SUV. It's been significantly upgraded for 2013, with an impressive list of tweaks to the exterior, interior, and available powertrains.

What you'll notice on the outside: new geometric wheel arches with a more demanding presence, a redesigned front fascia, oversize taillights, and chrome accents throughout.

What you'll notice on the inside: rich wooden inlays, jet-engine inspired air vents, and...