Which SDK should use any customers developing a new application ?

Centera SDK ?
XAM SDK ?

IHAC asking for the Centera development kit in order to develop a program to connect to Centera, were can I found that?

He has an AGFA IMPAX archiving in Centera, now he want to develop and add a new application in order to archive to the same Centera box, we plan to quote an upgrade of 8 nodes plus Centera pool license, should I need something additional?
 
IMPAX need CUA access, the new in house development are going to write through Centera API.