I've had a similar post but this one seems to superseed it.
With SP1 a proper method reducing this folder was added.
The WinSxS folder is used to store install and uninstall files, windows packages (current and previous versions of a component) and out-of-band releases. You should not completely delete this folder. Post Windows 7 SP1, there is now a way to remove the unnecessary files from this folder using the command line (elevated/admin mode -> Click Start -> Type “cmd” in Search. Right click on “cmd” and choose “Run as Administrator”).
Enter in this
dism /online /cleanup-image /spsuperseded
This is great for reducing the Windows folder size for SSDs and netbooks.
YOU WILL NOT BE ABLE TO UNINSTALL SP1 - Only dick with this if you know what you are doing.