I cant see why it should be hard to restore the original settings... I can just delete them from my autoexec.cfg and enable them ingame in the console (setting 1 instead of 0 for most of the commands).
I went to great lengths to explain why it could be hard to restore your old settings, especially since people using this program apparently don't know much about performance tweaking CVARs in the first place.
If you know all the settings the program writes to your autoexec.cfg then why use it at all? Again, I simply advise reading the following page and setting everything manually in your very own autoexec.cfg without the risk of the program doing anything undesired:
http://whisper.ausgamers.com/wiki/index ... xec_Tweaks
The main page has even more useful tips and tricks.
Even though futari linked to my post already I'll link to it again because I don't wanna read any complaints about messed up settings and how to revert them. ^^
THIS PROGRAM IS SHITE (link)