If you need or have a reason to buy Audi, you can go ahead and get one, please do not compare Porsche with an Audi. Porsche is far too serious a car to be messed about.
The relationship between VW and porsche is not something new in car manufacturing, most people that call Cayenne a Touareg are just not in real world, they haven't even driven both before, ask MikeS who has both cars he will tell you, they may look similar, but that is where the similatity ends, BTW I was one of those critisising the Cayenne until I test drove just the V6, I am telling you I took back everything I said about the car.
If you want a 4x4 get any 4x4, if you want a SUV, get Cayenne, there is simply no other SUV in the market today, remember Porsche specialty is building sport cars, we have been sold 4x4 as Sport Utility Vehicle, P orsche put an end to that. Enough said.