Lägga till Collectors Edition till vanlig D3-kopia?

You'd actually have to contact costumer service for that, they might be able to give you a key for standard edition and cancel the 4 months free subscription. As I read in a blue post that that is possible when you'd have bought the digital version, but I'm not sure with annual pass

The Collector's Edition is only available from retail, and that means to play as soon as possible you'll want to hit a midnight release to pick it up (or hope FedEx drops off your package super fast). We don't have any plans to release a digital CE, it's a retail-only kind of thing. But! you may have a few options.

If you have the WoW Annual Pass (or go sign up for it now) you get a free digital copy of Diablo III. This will give you the game right at midnight, you can go download right now, all that stuff. Then, when you pick up your CE, you can overwrite the standard edition license with the CE license and you'll be granted 4 months of game time (more or less equivalent to the cost of the standard edition). So that's a good option. More info also available in the Annual Pass FAQ.

Alternatively, you can get the digital version now, play right at midnight, overwrite your license with your CE when you pick it up, and then contact our support department. In most situations they'll be able to grant you a new standard key, which you can then give to a friend, or whatever.

Jag vet med all säkerhet att jag läst någonstans (på detta forumet) att man kan kontakta kundtjänst och "koppla bort" standardnyckeln så att du kan sälja/ge den till någon annan när du samtidigt aktiverar en CE nyckel. Det var någon som hade länkat just en blå post från US forumet, dock minns jag såklart inte vart detta inlägg är. Kanske i denna tråd men är inte säker.

Edit, du hann före

Ska Blizzard ta betalt sen eller vad menas med " 4 months free subscription"?

Läste detta på twitter

Har ingen aning om nått hur det funkar men kanske hjälper någon

https://twitter.com/#!/BlizzardCSEU_EN/status/202020446487580...

Your progress is tied to your Battle.net account, not the particular license you have. Upgrading from a normal version to a Collector's Edition provides you with the aesthetic items in the CE, plus, since you're a WoW Annual Pass holder, 4 months of time on your WoW account.

No, it will not affect your characters or progress.