The Spiess Supercar was commissioned by Robert Spiess to be constructed in his private factory in Gemmingen, Germany. Already a successful supplier of generators to the industry, Mr. Spiess hired Karl Heinz-Knapp (former Mercedes/AMG engineer) to create and produce the world’s first all-carbon composite sports GT car.

Callaway was hired to design and produce the engine package based on its experience with the twin-turbo Corvette program for GM. Full compliance with EC regulations, 600 bhp / 600 lb-ft torque, bespoke configuration, and production quality control were all requirements of the program. A unique intake manifold, twin AiResearch turbochargers, and specially cast exhaust manifolds resulted in a svelte package. The project was canceled before production began. However, the vehicle did meet all of its technical objectives.

There was a plan to manufacture 100 units of the car with a starting price of 500.000 DM (~255.000 EUR) which was later increased to 870.000 DM (~ 445.000 EUR). Only one complete car and dummy body were built. Due to the lack of demand, the project fell through.