The main problem with using the L5 in our car (a 2009 Opel Vectra), is that it just will not integrate with the cars radio system.
I can play music from my phone via a cable (mini jack) through the speakers. And I can charge the phone through the car’s lighter connector and a high powered (laptop) usb plug (although I did not check the dmesg messages).
But here is no way to connect the phone with the car’s bluetooth radio; so I can’t access the phones’ contact list, nor can I make hands free calls. So much for BT backward compatibility.