It's a totally separate client/install, so the full release will not be affected.
By Grace Benfell on
You can delete your Diablo IV Server Slam and/or Beta installs without fear. The full version of the game will be completely separate, which means you can uninstall without interfering with your main game.
This news comes from Blizzard itself, via global community development director Adam Fletcher on Twitter. He also clarified that the Server Slam and Beta files will not be updated and are a separate client. Basically, if you keep the Server Slam or Beta client on your computer, it will just be taking up valuable space that you could use to install the actual game (or something else entirely).
Just a heads up… you do not need to keep your #DiabloIV Server Slam clients. The full version of the game will be wholly different so there isn’t a need to use drive space for it.
Read more on gamespot.com