In my car, I have a Kenwood DNX6140 head unit which has native Bluetooth. Since receiving my Droid X, I have been able to pair the two devices fairly successfully. Though recently, I noticed that after I would end a call, the Bluetooth connection would drop and would not automatically reconnect. I wasn't sure if it was an issue with the X or the stereo.
I did notice there was a Bluetooth software update for the head unit from Kenwood. I was on version 1.7; they were up to 3.1. I did the update over the weekend and now I can maintain connectivity between the two devices.
However, now my phone book doesn't "sync" to the head unit properly. It only pulls over a handful of contacts and it displays them oddly. And I don't know which part of the phone it's pulling them from...it's like it's showing some of my Gmail contacts or something...certainly not my conventional phone contacts.
I don't know if anybody might have an answer for this, but I just wanted to throw it out there. I'm kinda hoping FroYo will help take care of the BT issues from the Droid's side...I'll just have to wait and see for that.