Yes you can easily get speeds of just over 20KBps if the signal strength in your area is good. These USB cards are EDGE class 12 devices.
My E51 is class 32 EDGE and I get over 25Kbps speeds at all times.
Cant really say if they are good for torrents coz I torrents clients never used to work for me. However while using the opera torrent client I could download easily. RS on the other hand works flawlessly at around 30KBps