To be honest, save the money and spend later when you have the info. Money has the capability of being saved and does not go rancid if you don't use it.
In general, pre-order is almost always a bad idea. If you want the bundles that is fine but note that the part that is exclusive to pre-order is a very tiny bonus. Ie, if you get heroic then you get the crystal of remembrance even if it is not a pre-order! Sure, if you're absolutely positive that you're going to buy the game anyway then pre-order doesn't hurt, but at the same time the bonuses are so trivial (xp bonus is pointless, war steed package is ok but you'll be identical to everyone else who pre-orders). TP purchase is the best deal as well if you have unused TP.
Remember last year when so many players were enraged merely one day later after pre-ordering? They said "never again!" Remember TWO years ago when players said "never again!"?
Never buy anything blindly, wait until you have full information.