Not 100% sure but any rental that I've had that had Bluetooth needed the phone to access the contacts even though they were synched. I don't think these are actually stored on the hard drive as you say but only synched to the phone. Plus if the car did not have nav it did not have a hard drive.Our new 328ix was in shop and they gave my wife a 2014 328ix for a loaner. The salesperson synched my wife's iphone to the loaner so wife could use Bluetooth. As part of synching, my wife's data was stored on car's hard drive. When wife returned loaner, she asked the service team to delete her data. The service manager told her no need, as 'data available only if that phone is logged onto that car's bluetooth' Is that true? Is my wife's data sitting out in some unencrypted manner on this loaner's hard drive? I searched for a thread that could answer this but no luck. Regards!