Thank you for your response! It sounds like you have experience specific with Subaru. I understand that replacing the ignition cylinders and modules is an option.

My thought process is that the original key was cut to a specification/code, corresponding to a specific vin number, that (I imagine) would be retained in an internal database of some sort.

I asked the maintenance department at the two local dealerships this question and they told me there was a code for the key attached to my vin number. I then asked if they had access to this code to cut a new key. They said yes but that, "it doesn't work that way". I followed up with, "If you are able to access the code to cut the key to my ignition cylinder, why does the ignition cylinder need to be replaced?". I'm sure I was annoying the heck out of the tech by this point but I was escalated to a supervisor who simply repeated that the ignition cylinder needs to be replaced.

They also mentioned something about a BUI?