Both my father and my daughter have the Parrot kit fitted in their respective cars, and it does indeed work very well. I could of course do the same, but the car already has a complete phone system built into it (though sadly without any kind of integral Bluetooth functionality), and it pains me to not use it if it's there. I might check with the manufacturer to see if there has been any upgrade to it in the last couple of years (the car's a 2008 model) which could now incorporate Bluetooth.
Further relevant postings on the topic are still very welcome.
Dee747