Originally Posted by zgmfx19a
2 is enough. Trust me, it's not worth the trouble doing 4 of those, especially when they are piss easy to get in the special dungeons. Instead, spend the time to get another Siren and/or Echidna. It's recommended for everyone to have two Sirens in their storage.
Also, updated page 1 a little.
Do the higher level masks only show up on the last 2 stages?