Selectively installing MS Office 2011 components
You can customize the Office installation, but I do not recall if that includes the ability to not install specific applications or not. Look for the "Customize..." button in the installer. 

The installer does require your admin password because it writes to specific system folders (as appropriate) which require administrator access. There is no avoiding that. 

However, there is good news: Office for Mac does not store your password, and will not install any background processes that would slow down your computer. Despite its reputation and many people's inherent dislike of anything Microsoft, Office for Mac is a relatively good "citizen" of the Mac community.