SAP HCM Implementation Standalone.!

Hi Experts..!

My client is looking for SAP HCM implementation only and rest of SAP Modules(FI, CO, MM, SD, PS) later on.

I know that SAP HCM implementation needs Company Code to move ahead which come out from FI, but apart from that what are other pros and cons of this SAP HCM implementation which would be considered before moving to this choice, Kindly also provide your expert opinion that what would be effect once other modules got implemented in future phases, especially FI & CO.

Looking for your advises and opinion.

Regards;

Bashir