I want to upgrade to a DSi, and figured I'd do the "transfer system settings" or whatever in the wifi menu. But I want to trade in my old DS to get a credit towards my next purchase. So I have some questions... Is this transfer really necessary? I figure at least all my win/loss records are tied to the settings, but are my nicknames registered as well? Do stores let you do this before you give up your trade in? If not, can I back it up to my PC beforehand, without having the second DS?