I will provide an honest answer. I trust this will be appreciated. Please remember that a low rating PUNISHES me for being honest and that I receive nothing for my time until a positive rating is clicked.
thank you for your attention to the rating requirement.
the smoke is being caused by leaking valve seals
this is VERY common on this model.
this is a huge job to fix and requires professional equipment and training. A 30 hour job when done right.
as for the drive malfunction, you will need to have the fault logs read from the car with a BMW scan tool to verify the cause, but based on what you've describved it sounds like you have a fialed steering angle sensor or steering column switch cluster which houses the sensor.
sorry if you were hoping for a different answer, but I trust that my honesty and quick response is appreciated.
Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle.