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http://automobileszone.com/blackwing-versions-of-cadillac-ct4-v-and-ct5-v-will-offer-magnesium-wheels/

Magnesium wheels have been around for decades and tend to be the wheel of choice for motorsport applications as they are low in weight and excellent at absorbing vibrations as well as dissipating the heat caused by this. A problem in the past has been corrosion, though new coating technology has largely eliminated this.

While some manufacturers are turning to carbon-fiber wheels for performance applications, a technology that results in even lighter unsprung mass, and all of the handling related benefits that come with it, magnesium wheels tend to be superior when it comes to absorbing vibrations and thus provide better ride quality. Magnesium wheels are also easier to produce in large volumes.

Gordon Murray is making magnesium wheels available on his upcoming T.50 supercar, and Porsche offered them on its track-focused 911 GT3 RS and 911 GT2 RS.

Cadillac still hasn’t said what will power its new super sedans, though the automaker has hinted at a top speed of over 200 mph for at least one of the models. Carbon-fiber seats will also be included, perhaps as an option. Judging by prototypes in the wild, the cars will also benefit from more aggressive aero and upgraded brakes.