I thought I'd share my little dramas with everyone in case there was someone else wanting to do the same - Note, the procedure should be the same for other mazda of the same year group (it works on RX-8's up to '07) :
I have an '03 RX-8, and wanted to get one of the new style flicky/switchblade keys. There are plenty of threads that involved the '04 onwards, but this information does not seem to apply to the '03, as far as what fob you need.
Several times FCC ID 41788 is mentioned, which seems to be the correct ID for the '04 upward. This however does not work with the '03, which seems to be ID 41847. This is a shame because 47188 supports trunk release.
I have gotten a key however, using one from an MPS6, ID 41521, and after programming it works a treat. Other than a lack of trunk release. I will check, but I'm sure this is also the key you got with the first of the Mazda3/6's.
For the record, the procedure for programming new key and fob:
Info pulled from: DIY: Code your NEW key yourself - RX8Club.comProgramming your key (you must have 2 other keys already for this to work!):
Use Key 1, turn to ON, wait till the key icon disappears and count 2 secs..
Quick.. pop in Key 2, turn to ON... wait till the key icon disappears, count to 2..
Quick!! Slam in the new key, turn to ON, and voila!!! If the icon disappears, your key is CODED!!
FOB Programing:
Ignition On/Off, 3 times,
Push door switch (the button on the inside of your door well where the car door latches/button that turns off your dome lights when the door is shut), 3times,
- Car will lock, then unlock-
Push "Lock" on remote, 2 times,
Push "Unlock", 2 times,
Push Trunk button, 2 times,