2009 Mercedes-Benz GL320 BlueTEC BASE PRICE: $58,200. AS TESTED: $71,125. TYPE: Front-engine, four-wheel drive, seven-passenger, full-size sport utility vehicle. ENGINE: 3-liter, double overhead cam, turbocharged, direct-injection diesel, in-line six cylinder engine. MILEAGE: 17 mpg (city), 23 mpg (highway). TOP SPEED: NA. LENGTH: 200.6 inches. WHEELBASE: 121.1 inches. CURB WEIGHT ...