1) While the player included in the Pro Client natively works for streaming, you are able to swap in another client if you desire. Go to Options -> Preferences -> Playback. Once in this menu, you are able to select from the dropdown list another player you have installed. Common players include VLC and Windows Media Player.
2) You generally need basic high-speed Internet (<1 Mbps likely won’t work well). The higher the available bandwidth, the faster the required pieces of the file can load and begin the streaming.
3) The torrent you download may affect your ability to stream because of its file format or size. Availability of the needed file pieces in the swarm will also effect the files ability to be streamed.