I like to use a box cutter to cut through the black sticky goop. It makes short work of it, and then when you're putting the plastic back on it sticks back onto itself.
Very nice video and explanation! Do you happen to have a detailed picture of the electric motor itself or a part number? Seems like a 22mm flat shaft one… looking for this info to search for replacements
Sorry I don't have anything specific, I did Google and use advanced auto search for door lock actuator to get matches but a Subaru dealership should be able to get you the part # if you call them.
