I tried with my WiFi Premium (3C8 035 730D) and it works fine with my S4, with Samsung built-in rSAP and with my app. I used the latest I9505XXUFNB8 (Android 4.4.2).
Most of the times the phonebook transfer kills the Bluetooth connection. Simply install the trial version of my phonebook app. If the connection is now stable, the Samsung built-in phonebook transfer is to blame.
BTW: this started as an Audi thread. As far as I know the VW Premium doesn't have anything in common with the "Audi connect" phone. Just to make sure...
Discussions about running the rSAP app on the Samsung Galaxy S IV