General Motors is investing $600 million in its Fairfax Assembly and Stamping Plant, which builds the Chevrolet Malibu and Buick LaCrosse. The automaker is using the investment to upgrade the plant, including adding a new 450,000 sq. ft. paint shop and installing a new stamping press. The automaker said vehicle production won’t be affected by the upgrades, and that the new paint shop will be housed in a new building.