car bluetooth (lexus IS 250 and lexus RX400h): will not disconnect automatically (ie. i leave the car, n900 still thinks it's connected). will also sometimes stay "connected" but isn't really nokia bh-503: works great for a2dp streaming, sometimes when i pick up a call even though the phone has the bt set connected, i have to transfer call to phone, then back to headset, to hear other person nokia bh-103: same issues as the bh-503