I was able to reprogram a Subaru Forester GT 2001 key with my Subaru Forester XT 2003. I am in Australia, but I’m sure this will work for other countries using both LHD/RHD.
nb. The Foz 2001 key now opens/closes the 2003 XT but you need to buy a replacement shell with a blank key. The blank key needs to be cut to suit your XT and the transponder from the GT needs to be moved across to it.
1. Unlock car with working remote
2. Take off drivers kick panel, join the two white connectors.
3. Take a seat.
4. Hold down the ‘door unlock’ button on the drivers door and whilst keeping it held down press lock twice on your remote. You will hear the doors locks open and close. You can now release your finger from the ‘door unlock’ button.
5. To program additional remotes repeat step 4
6. Get out of car, close your door.
7. Remotes should now work.