I had one of my master keys stolen last week and want to replace it with a new key ('99 323i). This is the old style key with the battery. I know that purchasing a replacement key and coding it won't prevent it from being stolen. My dealer recommends replacing the EWS module (supposed to be located below the steering wheel) and my indy suggests replacing both cylinder locks (driver door and trunk) as well. Has anybody done this before and is it worth the peace and mind of having your car not stolen? I've got 137K miles on my 3er so is it worth it to you?