Never had to buy these, what NA Subaru model would use same part?
I just ended up replacing mine, I bought an aftermarket set since I couldn't find anything that was definitive.
napolperformance.com
They make a set that will swap right over. They also make a coilpack replacement.
Its the same coilpack/plug wires as a Version 5/6 EJ207.
I do have an aftermarket set that I pulled OFF of my S/TB thinking it was causing an issue, however it ran the exact same after swapping.
PM me if you'd be interested in them.