Don't know about a way to auto sync all your previously downloaded apps BUT there is an easy way to get them back on the phone. Make sure you are logged into your google account on the phone, open google play, hit the lower left capacitive menu button, in the resulting pop up menu top of the list is "my apps", select that, top of the resulting window are tabs for "installed" and "all", select the "all" tab. The resulting list shows all the apps you have downloaded/purchased with the currently logged in google account. You can pick and choose which apps to reinstall. The list will show which apps are currently installed. I use this all the time because I frequently download an app for some purpose, then uninstall it, then later if I need it again I can go back and get it with relative ease.