Might want to narrow this down some. Fastest production car? Fastest wheeled vehicle on salt flats? 4 wheels?
I know its not correct to link a wiki, but it jives with something I was reading the other day. Bugatti had to rework the Veyron because someone else had a faster top speed. The new one has a top speed of ~268MPH, and is considered the fastest road legal production car.
Interesting, but the second sentence in your link reads,
The higher-performance limited production version, the SSC Ultimate Aero TT, is the second fastest production car in the world (behind the 2010 Bugatti Veyron Super Sport), with a recorded speed of 412.28 km/h (256.18 mph).
I believe I already linked the page on the Bugatti Vevron.
And LOL, I just read his post again, slower this time. I'm not sure there is a "fartest" car.