Um... maybe you should check the figures. The Cayenne Turbo S has 510 HP, which is a bit more than both the Wildcat and the Range Rover (which is heavier, too).
The Cayenne Turbo S goes from 0-62 mph in 5.2 seconds and reached to a top speed of 272 kph - that makes it the fastest (non-tuned) SUV on Earth, full stop. The only one coming close would be the AMG version of the Mercedes M-Class. But of course it's limited to 250 kph...
The Wildcat is made for bad terrain and is very fast there but it's not a car for the road or for race tracks.
If I'm not mistaken, the Cayenne Turbo was never timed on the Top Gear test track, which is odd, I think, but then again the review of it was more than just unfair anyway.
Thinking about it, the current 911 turbo was also never timed on the track, even though Clarkson reviewed it. Odd...
Well, better not to look at Top Gear and search for objectivity