“One of Cadillac’s plans for the next Cadillac CTS refresh is to make the CTS one of the lightest cars in its class. One assumes they will do this through additional use of Aluminum, and high strength steel. The advantage of high strength steel is that for the same properties a thinner, lighter piece can be used that has the same or better strength and durability.
There is a 2-3% improvement in fuel economy for every 100 kg (220 lbs). So although the EPA cycle is complex, in general a 28 mpg CTS might break 30 mpg with the loss of around 500 lbs of weight from its 3,681 lb curb weight. Obviously there is a limit to the fuel economy that can be gained in this manner, since Cadillacs one can safely say will always have some weight. Cadillac’s goal of being the lightest in their vehicle class seems ideal. This goal is one that will have to be revisited in the crowded markets Cadillac competes in.”