The DLC skin also allows you to upgrade his blade
As a reminder, all Europeans will be getting the Gray Fox costume DLC packed into Metal Gear Rising: Revengeance for free. This is the same DLC that US folks are required to pre-order to obtain.
This was revealed nonchalantly in the past, but Konami has just announced that you'll be able to upgrade the new weapon unique to the skin, the "Fox Blade."
As I've said before, skins help me increase my replay value with action games, especially if they have extra abilities or weapons like this one. My playthroughs on the harder difficulties will be spent with Gray Fox, for sure!