I HIGHLY recommend that before you install Mitsu's pack -- or any other comprehensive package of sounds -- you make a copy/backup of your original AH sounds folder.
Just copy/paste the sounds folder from AH to someplace else for safe-keeping ... or siimply rename it something like sounds_old.
You might find that there are some of the original sounds you prefer to Mitsu's. If you don't back up the originals, you'll have to re-download them from somewhere.
Just sayin.
Splash1