All I can comment on is that when I tried to order a 683 adapter, the part comes up as No Longer Available in the computer. When I ask what is replaceing the 683 adapter, the reply from BMW was
For the iPhone USB adapter, use the updated p# 84 21 2 158 682 instead of '683. To use 682 the vehicle needs to have the upgraded version of USB kit.
it can be factory ordered or may be retrofitted according to the vehicle.

Perhaps the 683 can still be ordered in the states. The same could go for 84 64 0 307 591, upgrade kit for bluetooth with USB/Audio interface.

Craig