20KB/s is average for me on files with around 30 peers. 230 was my max, just something I was pointing out because I've never seen my machine get over about 15KB/s on Kazaa or other P2P clients.

Do you mean your network has slowed even when the torrent window is closed? If the torrent is going, it's not suprising.

As far as clients go, I'd suggest Shadow's Experimental, also called BitTornado, though others here have other programs they use. I just like that one for its simplicity, and I like having seperate windows for each download.