The 2012 Buick Regal announced with assist fuel-saving technology, which improves overall fuel economy by 25 percent over the 2011 four-cylinder, six-speed power-train. Estimated fuel economy is 26 mpg city and 37 mpg on the highway.Lightweight 17-inch alloy wheels and tires with lower rolling resistance. A driver-selectable, fuel economy-optimizing mode for the air conditioning system, which enables more frequent and longer-duration engine stop periods.A 2012 Buick Regal higher-performance version of the recently introduced 2013 Regal. A handsome body kit, 20-inch wheels, and larger brakes increase the GS sportiness quotient.While Europeans will get an Insignia OPC with a 325-hp, turbocharged V-6, the GS gets a higher-output version of the 2.0-liter turbo four found in the Regal. In this case, it’s rated at 255 horsepower, up from 220. All-wheel drive will be standard. Look for either a six-speed manual or a six-speed automatic transmission.