I don't really see what so special about the X6. From a technological aspect is no different from the Cayenne except for the sloping roof. Heck I've yet to read a first drive of the X6 which state say that it's profound in any way.

As for the new Cayenne it will be more urban and light weight than the the current one, think Infiniti FX. It will sit lower as well as sportier increasing the "Porsche" experience.

The engines currently used in the Cayenne are well engineered, absolutely perfect and I count on them carried over to the next generation. Audi has some amazing engines these days and I bet that Porsche has been eye balling them, so it wouldn't surprise me if the new Cayenne share one or two engines with the Q7.

Since the new Cayenne will really serve as a Panamera estate/touring I'd expect them to share some new technological innovations that Porsche have up their sleeves. The turbo might likely get VTG, LED tail and fog lights should be standard. Overall it should be a vast improvement of the current generation which really wasn't more than a short project for raising big funds in a short period of time.

Here are pictures from last year of a mysterious Porsche mule, which is believed to be the next generation Cayenne. It was said that the car was taking bends at insane speeds.