A 1989 Ruf CTR ‘Yellowbird' recently sold for over $6 million at an auction, becoming the most expensive Ruf ever sold.The car, finished in Blossom Yellow paint, is one of just 29 examples ever built and features the lightweight Leichtbau package.Powered by a twin-turbocharged 3.4-liter air-cooled flat-six engine, it produces 463 horsepower and 408 pound-feet of torque.Ruf owner Alois Ruf noted that the CTR Yellowbird is a significant turning point for the brand and for modern performance cars.