Anybody with one key should consider seriously using Autokeys Express to obtain a key which is capable of mechanically opening the door at the very least.......
LINK
So if the worst case scenario is realised and the working key is lost, a transponder can be programmed to enable the car to be started.
I gave this advice to a customer six months ago, sadly it was not heeded and when he lost his only key, I had to order one from BMW.
The cost was £220, compare that to the cost of having a key produced by myself, or indeed any of the other traders offering replacement key services.
If the OP wishes to have a transponder programmed to make a spare key which at least will start the car, then I'm more than happy to assist
Brian
