APEX

Seeking feedback/thoughts on this general question.

I am maintaining an APEX application that utilizes multiple schemas all residing in the same database as APEX. I am wondering what might be the pros / cons of putting APEX in a separate database and server.

Would this necessarily yield security or performance benefits (or costs)?
How many changes would need to be made in the APEX configuration and code? I have read here in the forum that at a minimum database links would need to be created to the utilized schemas on the other server, with appropriate grants. What else?

Thanks.