The clashell uses ata2 hd's (source: [http://www.everymac.com/systems/apple/iBook/stats/iBook.html|everymac.com])
conrad is great - i'm almost every week at the store in nuremberg ;-)
ultra ata is only a different name for ata2 (source: [http://en.wikipedia.org/wiki/AT_Attachment|wikipedia.org])
have fun in good old germany (btw - the weather is great at the moment ;-) )