Ok, it turns out I didn't need that "system.cfg" file. I just needed the tweaked CVar settings. But thanks for your help agentkey.
The file that I downloaded is attached below.
Just replace all the files in your "x:\Program Files\Electronic Arts\Crytek\Crysis\Game\Config\CVarGroups" directory. This gave me all the high detail settings such as Paralax Occulsion Mapping, Sun Rays, and high detail water.
Sorry. I'm sure this has been posted before.
Here's the original download link:
I didn't think the Demo settings were compatible with the retail version, but apparently they are. Thanks for your help guys.
Another thought. Is there a way we can change the title and sticky this so that a new topic isn't started every time a person wants to make their DX9 machine "Uber high"?