This came as a bit of a shock to us, but the Bugatti Veyron is not actually the fastest production car in the world according to that authoritative tome of useless and wonderful knowledge, the Guinness Book of World of Records. It seem Bugatti just never got around to scheduling an official high-speed run that could be officially considered by Guinness. In late October, Bugatti plans to rectify that and make an official top speed run at the Ehra Lessien test track near VW's headquarters in Wolfsburg, Germany. The track has an unbroken straight of 9 km (5.6 miles), which should offer ample room to reach the Veyron's "unofficial" top speed of at least 253 mph. Currently the Veyron only holds the record for the Most Powerful Production Car.
If the official fastest production vehicle isn't the Veyron, then what is? The answer is the Koenigsegg CCR, the 806-hp super Swede that has been officially clocked at 245 mph. The Veyron may not be king of the hill for long, however, as the CCX that Autoblogger Frank Filipponio got to pilot can theoretically reach 258 mph.
[Source: Motor Authority]