As seen on Top Gear: fastest production car speed record: Bugatti Veyron (8.0 litre W16, 64v DOHC quad-turbocharged petrol engine, 1,184 brake horsepower, 0–300 km/h in 16.7 seconds)
Bugatti's official test driver Pierre Henri Raphanel piloted the Super Sport edition and was clocked at an average of 431.16 km/h. 
Imagine driving that on the German AutoBahn(link to fastest production BWM doing 330).
My speedrecord: 245 km/h, in an 25 years old Porsche 924 on the AutoBahn, A57 Köln- Nijmegen.
Yours?