Adding files to the DPR file vs project paths in Delphi 2010

Question

We are just migrating from D7 to D2010 and are having a debate about cleaning up the project paths. We have a number of directories with a large number of Pas files that are

Answer 1

Having all your units explicitly in the dpr immensely improves compilation time, code completion, error insight and general navigation.
It does not prevent you from keeping your files organized in folders and sub-folders, but just don't rely on the different paths to find them.
On a big project with millions LOC, it makes a huge difference.