Thanks Adrian,
Switching with VagCom is nightmare
Then it boils down to finding iphone cradle kit that can:
* Prodive power
* Use OEM external antenna from the old OEM kit
* Can possilbly be mounted in passenger armrest where stock phone was located
* Nice to have: Music interface with RNS-E by wire
Since voice connection with RND-E will be done via bluetooth, then the biggest challange is support of OEM external antenna.