Georg..... I wouldn't go as far as saying there was any cheating but I hope we can all agree that the Kyalami result is a freak..... the results observed there are not in line with results from other tracks and trusted sources.
eg. Autozeitung X6 is slower (quite a lot slower) than the M5, M6 X6M, M3, RS4, S4 S3, etc.....
at the Ring the X6 is wayyyy down the list and is slower than the likes of the Golf GTi (even the crappy Mark 4), Opel Corsa OPC, Clio Sport etc. in fact on the majority of tracks we have times for the X6 is slower than ~75% of all other tests.
I'm not saying the Kyalami test is invalid just that its unusual....... we are all smart enough to see the facts and only an X6 fan boy would use the Kyalami result to say "X6 beats R8!" (ignoring the change in track config as well ;-)