I know a few people that have 64kbit upload streams and they have always been able to upload at 5kB/s without harming anything else. Basically, Lowering it any more defeats the purpose of scrweing leechers over. Like I and nefarious said, Even with only 4kB/s, which any 64kbit upload stream should be very well capable of, you get 24kB/s download which is almost all of your line.