I've got the enhanced edition of original sin. Now I see a 'collectors edition', that only got a few more items.
No upgrade, no possibility to add the added items, but I do have the generous option to flog out over $70 to get the missing pieces (batteries not included)

Thanks! ;) I'll bite... not.. Guys, (in the unlikely event you read this) please don't be like that.

There was a separate upgrade DLC for D:OS, but the soundtrack, art pack and design documents are only included in the 2 pack Collector's Edition for the EE (the in-game DLC / CE items from D:OS are included in the EE for everyone).