On my machine I reduced the WinSxS folder size with 1183 mb (1.241.054.572 bytes) using a new feature called delta compression.
Note: If you are using Windows 8.0, first install KB2821895 “A servicing stack update is available for Windows RT and Windows 8: June 2013”
Note 2: Current installed Windows Updates can not be uninstalled after following the steps listed below.
Open an elevated command prompt and enter this command:
DISM /Online /Cleanup-Image /StartComponentCleanup
Wait patiently, this will take a while. On my machine it took close to an hour to complete.
Before & after (make sure to look at the Size on disk).
Consult the cbs.log file if you experience any errors.