Fastest pitch is not something we can measure in practical, and certainly no one has statistics on it. Fastness of a cricket pitch is how batsmen and bowlers feel when they play on it, the sound of the ball thrusting into wicket keepers gloves, mostly above the hip height cause a pacey pitch will always have bounce associated with it.
Now by my experience of watching almost all international cricket that has happened in last decade, I can assure you that Centurion is not really the fastest I've ever witnessed. Perth in Western Australia has been tipped as the fastest but it too has slowed down considerably since the days I watched Windies play on it. Having said that, I'll regard Perth as still the fastest in the world. Second, if you ask, one in between Newlands in Cape Town and Sahara stadium in Durban will take my vote. New Zealand venues too have some speed left to it on which genuienly fast bowlers can clock 150kmph. Barbados is still a fast bowlers paradise.
And no, S Sreesanth took his 8 wkt haul against South Africa in 2006 at Wanderers ground in Johannesburg, brining India her first test and only victory in South Africa till date.