Questions unclear. There are several components of a port. The ports tree (/usr/ports) files in a port subdirectory, the distfile that's the actual source, or maybe packages. Distfiles are usually downloaded when needed.
"driver installation"? No idea what is being asked. Ports and drivers are generally not related, although there are some add-on drivers that are in ports.
Can't tell what "disturbing previous installations" means, either. Please, if you can be more specific it would be easier.
