Please tag your post with either msfs-2020 or msfs-2024 if you would like to discuss a specific sim.
I swear after Boris sound mod for the 777. I’m dying for any sound mods for the default Aircraft such as A32N/A330. Is it not possible to mod the aircraft due to encryption ?
If you have the ability, you could create a mod in the manner done by Boris, but you cannot alter the existing files, as you have mentioned, they are encrypted.
Moved to User Support Hub > Aircraft & Systems and modified title for clarity.
I’ve never tried it, but say for the 320 Neo, would it be possible to copy the FBW version (which is actually made by Boris), name all the folders and files appropriately to match the ini 320 Neo? Look at how Boris has set his up for the 777 with all the .json, manifest etc…. Maybe it could work (doubtful, very)?
Looks like all the default aircraft literally just have a .pck file which from what I’ve read is just a packed project, kind of like a compressed file (zip). This excludes the PMDG 777 which doesn’t even appear to have a sound folder. 
Ah, the good old days of FSX, any panel, any sound pack interchangeable with any model.
Boris stuff is top notch, have it for the following;
152 - Default
172 - Default
CRJ - Aerosoft
737 - PMDG
777 - PMDG