You don't need D3edit, you need an MN3 extractor and a text editor. Some serverops however try to insist that you need to edit the MN3 itself (which corrupts it), which is simply not true.
Guys, guys... chill.
Yes, you can edit the links via D3Edit.Yes, you can edit the links with the MN3Edit tool.
The point is that server-ops (including me) need to be watchful about broken auto-download links.