These torrents include tracks that can be previewed on the SXSW website for SXSW 2015. This year’s includes 1,291 files totaling 8.42GB, making it the largest to date. Note that the filenames and ID3 tags were updated to properly reflect the artist names and song titles.
Note that 64 tracks that were included in the first torrent were no longer available on the SXSW website as of the release date of the second torrent. That list is here for reference.