The virtualisation server doesn't connect to the authoring instance via HTTP, so changing the HTTP port for the authoring instance shouldn't have any effect. It does, however, connect to that instance via RMI on port 50500, so if you've changed the RMI port then the virtualisation server will definitely need to be reconfigured.
The virtualisation server is configured via files in virtual-tomcat/conf - in particular the two alfresco-*.properties file.
Cheers,
Peter