Despite a curb weight ranging between 4,722 and 4,936 lbs. (front-wheel drive and all-wheel drive, respectively), the 2007 GMC Acadia's standard 3.6-liter V-6 engine performs admirably. That' because those six cylinders work to pump out 275 horsepower and 251 lb.-ft. of torque, which while not overwhelming, proves to be quite capable of moving the heavy Acadia with ease. Power delivery is seamless thanks in part to the 6-speed automatic transmission, which we were happy to discover included a manual shift feature. Less impressive was the 14.9 mpg registered while driving an all-wheel-drive Acadia SLT1, a far cry from the 17-mpg city and 24-mpg highway ratings from the EPA.