Yea, they will come back.
How do you plan for them to get updates?
Basically, you should be able to remove via add/remove programs, if that fails, use Cleanwipe.
SAV Uninstall docs:
How to uninstall Symantec Antivirus, Symantec Endpoint Protection,and Symantec Endpoint Protection Manager, and what to do if that fails
http://www.symantec.com/docs/TECH104790
Manual uninstallation documents for Symantec Client Security products
http://www.symantec.com/docs/TECH99631