How can I export my system preferences?
I wrote some scripts to backup and restore Mac preferences. It does both System and Application preferences.

You can grab them here: https://github.com/clintmod/mac-preferences-backup

They're pretty simple. I just loop over the domains from running defaults domains and then call default export [domain] [plist file path].

Then to restore I just loop over all the plist files in the dir and run default import [plist file path]

You can modify the config.py file if you want to backup to a different dir. The default dir is ~/Dropbox/MacPrefsBackup.