For 2007 MS3.

 

You can get a standard transponder key cut and shipped for around $30 from www.onlinemazdaparts.com. Otherwise you can purchase a third party blank from sites like dealextreme, ebay, amazon, etc. Mazda uses the same transponder chip in all their keys so you shouldn't need to worry about compatibility.

As far as programming that is a very important subject. If you have two working keys then you can program a third one (it can accept up to eight) yourself in about 15 seconds. If you only have one working key then the dealer will need to connect to your car's computer, manually remove the existing key codes, and manually add the new/existing ones in. The process takes about 45 minutes and generally will cost you an hour of labor charges. Once the second key is programmed you can go to the self-programming method and add more keys.

If you are having a second key added then get two keys. Have the dealer program one key and then program the second one yourself. That way should you ever lose the third key you still have two keys and you can replace the lost key and program it back in yourself. Cheap insurance.

 

How do you do that?

 

Have all keys in hand which you want to be programmed ultimately. This includes both new keys and already programmed keys.

Insert working key #1, turn to ON position until the immobilizer light turns off

remove key and within 10 seconds...

Insert working key #2, turn to ON position until the immobilizer light turns off

remove key and within 10 seconds...

Insert unprogrammed key #1, turn to ON position until the immobilizer light turns off

Repeat this last step for every new key to be added (up to eight). Remember you have to have two working keys for this to work.

 

Good info, thanks! And FOUND!