exporting the registry is a good idea, you can do that off the box, too.
If you are going to start your tweaking, you're going to be using the system restore to create restore points, or you are going to be exporting your registry allot
easiest thing for the system restore is to create a shorcut to the restore button on your desktop;
use this target;
%SystemRoot%\System32\restore\rstrui.exe
huge time saver