I just want to let you guys know that you can pretty much program a new key fob for the twin.
In my experience I was able to program a new Key fob for my 2017 BRZ using SSM4 and getting a CLEAN [virgin] key fob from Ebay.
Again, it has to be a key fob that is ready to be programmed. Any used key fob already programmed with an existing vehicle WILL not work until it's dis-virgin as long as the key fob FCC ID matches your existing one.
In my case the FCC for my key fob is HYQ14AHC. you can find that at the back of the key fob.
So any Subaru key fob works as long as it matches the FC ID - it's interchangeable between Subaru vehicles.
All you need is a copy of :
1. SSM4 (depending on the copy you get you might need additional software to be able to use it - hit me up if you need a copy
)
2. Tactrix Openport 2.0 OBD adapter (or of the J2534 certified dongle)
3. and of course a virgin keyless entry FOB matching your existing FCC ID fob (hit me up if you need find a good source for a cheap one)
Good luck.