Originally Posted by garment69

If your phone is paired to your headunit and you park your car, when you return the phone should link up automatically. I dont think any of us have seen an issue where it is not. If, however, you are changing to a headset when you leave your car and pairing your phone with that, the headunit will not reconnect unless you select it in the bluetooth settings on the phone.

For you last question, if your headunit supports both handsfree and A2dp you will be able to also have a bt gps unit running.