Hi Simone,
I do not know about C++ Builder, but the DI API works the same as any other COM based interop (same as for example MS Office Interop).
The DI API works most reliably when its version (including patch levels) is the same as that of the B1 system, that you run your application on. That means that over time you will need to upgrade your application / the reference to the DI API as many or as few times as the customer(s) requires.
So you should probably choose the method that will make upgrading your application as easy as possible.
I do not know if for you that means a wrapper, or importing.
Regards,
Johan