In-Context or new part file?

When modifying a vendor part, should in-context modeling(external references) be used? What is the recommended practice?

I need to have cut-outs added to in the end-plates and the PCBextrusion for the electrical connectors, and switchs. I also needholes for mounting a cooling fan & slots for airflow. As eachplate / extrusion will have its own part number, should I refer tothe vendor part and indicate the additional features to be added,or create external references in the part to the vendor part? Whatare the Pros & Cons of this method?

Are configurations another option? With in-context modeling, if thevendor part changes, other future parts that reference this partwill change as well.SolidworksGeneral