The most difficult of challenges I have faced during an integration is related to resources. We were able to overcome this challenges by developing an enhanced capacity model and engaging resource managers earlier in the process in an effort to identify required resources by area.
Hi. For me it is usually cultural clash. It may be very challanging to introduce at the targets the practices and procedures implemented in your company.
While staffing is one of the critical challenge for integration execution. I would say striking a balance between the Capex and level of transformation / rationalization you would want to achieve with the integration is one of the most complex element of integration in my view.