Not really, none of us have a car kit. Actually, I only know one person with a car kit in any car nowadays, as handportables/small handsfree kits are so cheap now.

We can test it by connecting/disconnecting wires, but that's about it, hence the configurability. Current suspicions on mute involve needing a pull up/down resistor on the sense line to ensure that it goes the other way when the phone isn't in use.

Hugo