Originally Posted by Qsilver7

If you order a key from BMW...it will already come cut for the cylinders and contain the correct EWS "ISN" (individual serial number) required to start your car. All you have to do is insert it into the lock cylinder or the ignition and it will lock/unlock your car and start the engine.

If you purchase a remote key, the only thing left to do is program it for FZV/DWA (remote central lock/unlock & arm/disarm)...but you can do that right in your driveway or the dealers parking lot...we post that information here at least 2 or 3 times a month.

I don't know what a key from a non BMW dealership will do...you'll have to inquire with them. BMW doesn't share their database with anyone else...but some people have invested in equipment that can read your control modules to access the ISN, then write to a new EEPROM (chip) that can be used in a key. But again, you'd need to inquire with the seller of the key if they are including this service along with the key...if they don't, then all you're getting is a blank key that will need to be cut by a keysmith...and it will be up to you to find someone that can read/write to the key's chip for it to be able to start your car.