Most, if not all, relevant files are available on GameFront. GameFront, however, does not provide access to downloads world-wide.

ModDB also provides some of the essential files.

The following files are also available via torrent:
ESF 1.2.3 Beta (Stable, what you want)
ESF 1.3 Open Beta (Unstable, definitely not what you want)
ECX Big Pack 8.4

Please bear in mind that torrents depend on sharing. Keep finished torrents running.