I managed to get a VISEEO Bluetooth Phone kit from a breaker for half the new price. It was a simple fit in my 2003 Cayenne.
1) Pull the lower rear panel from under the Drivers seat to gsin access to the telephone module. Un plug the fibre optic wire and connect it to the new Viseeo box.
2) The Viseeo box has a positive and a negative wire for power. Simply "scarf" into the power old module power line and hey presto BLUETOOTH Instantly!
As soon as I enter the car it is ready, it shows a full signal on the PCM screen. I can select the phone book instantly and all the existing multi function controls on the steering wheel work perfectly just like a factory installation!
When a call is made or received the radio is automatically muted and all sounds are through the car speakers crystal clear.
One last thing was to put the supplied mic in a decent position. I put it at the top of the panel at the side of the windscreen, thereby concealing the wire so again it is hardly noticeable....
I have to say this system (sold in the UK about £300) Is SUPERB. Very little if no background noise and no hiss whatsoever. Recipients of calls report the same great call sound and actually I have had comments like "you are obviously on the house phone?" That is how (noise) quiet and clear this system is.
So in conclusion, I give it 100%, and I do not, do that lightly, try one you will wonder why you waited so long, because Bluetooth in your Porsche is the icing on the cake! Regards Dave Newby