Wow, that's totally peculiar. Maybe iDrive handles voice? I think it was pretty rare to find a car with iDrive but without bluetooth, although I could be talking out my ass.
Anyway, we'll definitely need to run wires in your car. It'll be a pain, but whatever. Mine will be a guinea pig first. Like you mentioned, I actually can use the phone just fine in the cabin, although if it's in the front seat the bluetooth is a bit raspy whereas if it's in the back, it's better. Point being, all my antenna orders are coming from china, but the wire is coming from the US and the mic is probably coming from the dealer down the street, so I might even be able to wire everything up next weekend and just deal with the crappy BT reception until the antenna parts come in.
Now I just need to track down pins for the mulf connector, and, ideally, a connector for the mic.