I don't know everything, of course not. I'm not working for Porsche and even Porsche employees don't know everything. This is impossible because there are a variety of jobs and locations.
But there are a few things, like the "I have a friend at Porsche" story which are 100% untrue. I know that because I know some pretty wealthy Porsche customers with high up relations to Porsche and they didn't get what they want or had to pay a lot of money for it. I know what is possible and what isn't, there are a few mods which were possible for "good friends" but of course not for free.
The Cayenne Powerkit wasn't among them, this is 100%.
Trust me or leave it. And if your friend sold his CT, he surely still has the VIN number somewhere. Just ask him and pretend you need it for something else. This is they only way how to unveill such lies because there are no "unofficial" or "official" Porsche technical mods without Porsche attaching the updated data to the specific VIN number for further reference and legal issues.
Porsche is not a Tuner, if a customer has an accident with his modded car, they have to help with the investigation if the legal authoroties and/or insurance asks for it.
This is why they never would do unofficial mods, unless they're actually official and there is a technical certification for them. One reason why your friend wasn't able to have the powerkit a few months ago is the fact that rim development wasn't finished yet (due to the bigger brakes). This is why Porsche started to produce new 19'' and 20'' rims with modified spokes and these modified rims are installed from June 2004 builds on.
The VIN number says a lot about a car. There was a guy who claimed he has a 993 Turbo S, however his car looked a bit different, more aftermarket, despite the double exhaust pipes and the Turbo S badge. I asked a friend to look up his VIN number and this car was just a normal 993 Turbo without even a powerkit, standard power. When I confronted the "Turbo S" owner with that at a meeting, he denied everything and he was very furious. Surprisingly, a few days later, the Turbo S badge disappeared from his car.
I'm afraid this is part of human nature, especially when it comes to cars. We have to make people believe we have something special and the sad part is: most people believe it.
I can't change it, you can't change it, this is how life is.