ShadyMac wrote:
Typically the none support of certain features is more to make it a general use profile and not specific to technology found in certain vehicles and not others...
It has nothing to do with specific car manufacturer. AVRCP has several versions of its specification, and it seems iPhone implements one of the older ones (probably 1.0) that has only very basic functionality. Newer revisions of AVRCP support additional features, such as metadata about song currently playing, browsing capabilities, etc. All of those features are part of AVRCP specification, they are not special extensions for specific car makes. AVRCP 1.3 or 1.4 are general use profiles.
To correct one other poster, file sharing (FTP - File Transfer Profile) is not needed for phone book sharing. Device needs to support PBAP (Phone Book Access Profile).
For nice summary of Bluetooth profiles, there's this nice wikipedia article:
http://en.wikipedia.org/wiki/Bluetooth_profiles
Unfortunately, tech specs on iPhone page don't show exactly what profiles and to what degree are supported, but I'd guess it to be limited to HFP (possibly not all features -- dialing last number didn't work on my HFP headset?), HSF, A2DP, and an older revision of AVRCP (again, missing some features).