Mark Reuss, EVP of global development at General Motors, told The Detroit News in October, "We will create with the CT6, the world's most advanced body structure... [and] it's not aluminum. It's a stronger, smarter, safer premium luxury vehicle." It echoed the earlier Automobile story in saying the CT6 would use GM's "patented welding technology with high-strength steel, aluminum and steel stampings and castings."
That same month, the Wall Street Journal ran a piece titled, "GM Won't Follow Aluminum Strategy in Future Cars," in which Reuss said, "making big statements around all carbon fiber, all aluminum, all magnesium, they're very interesting," and that GM wouldn't be doing it. That piece also circled back to a material mix and GM's special welding process, saying the CT6 "will have a body made of aluminum, high-strength steel and other materials, and will be 100 kilograms (220 pounds) lighter than a similar-sized car made of high-strength steel."
We don't know what kind of body Cadillac's new assault on luxury is going to wear, but now we can't wait to find out.