Another question on keys

[RickR]

I'm looking to purchase a 1986 325, manual 5 speed that has been in a storage lot for about a year. Not much is known about the car other than it was driven and parked there and the owner never returned. So there is NO key.

You guys have been very helpful with how to go about getting a key, but if I were to purchase this car, what happens if the ignition has been changed and bmw cannot make me a key? Is that possible, or is the anti theft such that a key is programmed in such a way that bmw would've been involved with any changes?

Please let me know your thoughts.