Game is content complete if you buy the most expensive version. Europe got an exclusive resource pack for some reason.

Pre-order bonus was getting the deluxe upgrade pack for free.

Pre-order bonus - Early Bird DLC

Pre-order bonus is a special tank for your mouse pet and the Sunset Dye.

White Equipment for Ramza, Weapon: Mythril Knife, Accesory: Spiked Boots (Increase Jump) ARE PREORDER ONLY EXCLUSIVE ITEMS. Also consumables: High Potion x10, Ether x10 with pre order. Pretty lame...

Pre order content: Planet Diving Suit for EVE (White Edition), Classic Round Glasses for EVE, Ear Armor Earrings for EVE. There's no mention of these items being available for purchase after launch.

Exclusive vehicle for pre-ordering: Aramatsu Bowhead 30T

Various promotional items from different sources.

Pre-order bonus was a resource pack.

An item to get you more experience and a resource pack were the pre-order bonus.