Mercedes' seven-passenger SUV is freshened for the 2017 model year, with revised interior and exterior styling, a nine-speed automatic, an upgraded air suspension, and the addition of the current--and more complex--Mercedes-Benz infotainment system. Our last tested diesel GL was plush and quiet, with supportive seats and a third-row seat that was roomy enough for adults. It had a steady and comfortable ride, but the GL proved very clumsy when pushed to its handling limits. Engines include a 362-hp, 3.0-liter twin-turbo V6; and a 4.7-liter V8 that puts out 449 hp. The flagship AMG GLS63 churns out 577 hp. Available safety equipment includes cross-traffic alert, blind-spot warning, and lane-keeping assist.