After a four-year absence, Porsche will be making a comeback to the 2011 Detroit Auto Show with a "spectacular new concept that points towards a future road going model." This new concept car is closely related to the 918 Spyder concept from which it takes key components, including elements of its platform. "Porsche’s return demonstrates the relevancy of the Detroit show for luxury manufacturers," said Rebecca Lindland, an analyst at IHS Automotive in Lexington, Mass. "They target a very specific audience with their cars and the U.S. market is incredibly important for Porsche." The German publication, AutoZeitung, suggests that this new model is known as the 929 and that it will be revealed sometime in 2013. A hybrid drivetrain that will combine a 4.8 liter V8 Biturbo engine with three electric motors, something similar to the 918 Spyder, is expected to be found under the hood. "We’ll have something spectacular to show there," H