Download all translations as a single tarball offer which compression to use

When wanting to export all translations for a package, you may select .po or .mo file formats and then they are made available for download as a single tarball.
They are made available as a .tar with gzip compression (.tar.gz). I propose that a compression method may be selected by the user. i.e. .tar.gz, .tar.bz2 and .tar.xz
This is in order to save bandwidth for launchpad and the user. It would also speed up downloads on for users on slow connections, as well as the benefit of saving space at the users' end whilst the file is being stored.
GNU Tar v1.22 allows .tar.gz with the -z flag, .tar.bz2 with the .j flag and tar.xz with the -J flag (providing that is how the Launchpad server creates the tar-balls). This could be a very simple feature to offer, with the savings of Speed, Time, Bandwidth & Space already mentioned earlier.