This script replaces URLs of peoples profiles in the main stream; where the posts show, to a site that grabs their twitter ID #.
Example 1 (image)

You can still go to their twitter profile URL by hovering over URL and clicking their profile URL in popup preview.
Example 2 (image)

shows user ID number once URL clicked (image)

1. Make sure you're running Firefox on desktop
2. Have Greasemonkey installed
3. Install this script