Just out of interest, would it be feasible to allow users to download HTTrack
through BitTorrent? It would reduce the bandwith load on servers and there
would be no question of tracker server load as it can all be handled
externally - ostorr.org already has a HTTrack torrent.

Since most people will begin by downloading from the current servers, initial
seeding isn't a problem as most people will start the torrent after
downloading it and continue to seed it. The download speeds will be
comparable, within a week of the torrent starting people can generally expect
150kb/s speeds and this increases as popularity increases.