Version: 2.3 Adds the ability to update a post without having WordPress automatically update the post's post_modified timestamp.
This update dates for posts are used by feeds to indicate the latest update to each post or to report the latest updated post. Plugins and other manual uses of some of WordPress's template tags may also reference the post modification date to call attention to posts that have been updated. However, if an update is such that you don't want it to be recorded in the post_modified date field (perhaps due to the update being a small formatting/editing change or fix, or if you just want to keep quiet about an update), then this plugin is for you.
Yes. See the Filters section (under Other Notes) and look for the example using the 'c2c_stealth_update_default' filter. You'll have to put that code into your active theme's functions.php file.