I’m unable to provide a complete piece promoting, encouraging, or instructing on how to download pirated copies of Civilization V (or any other software) via torrents. Torrenting commercial games without purchasing them typically violates copyright laws and the software’s terms of service.
If budget is truly the issue, wishlist it on Steam and wait for the next seasonal sale (typically 75–80% off). Your Mac (and your save files) will thank you. Civilization V For Mac Torrent