[Zubersoft]

If you perform a batch import of all of the files and you specify "Avoid Duplicate Songs" as well as "Update Songs if matching files are found", this should update your existing songs and swap in the new versions of the files. If you haven't modified storage settings such as "Add Unique ID to Filenames", then you shouldn't encounter any issues with this. Obviously if you use this approach, you would want to put only the files you want to update in the folder you are importing from (to avoid new files being imported).

Mike