With the new version of emule, i've set upload speed to 10kps, which seems to have the effect of uncapping the download, so my download's at 999kps. For me, i connect to both the KAD network (much, much more files), and razorback2 (or whichever server has the higher userbase). Make sure all of your ports are forwarded, so that you get a HighID. Now everything should be fine, it might take emule awhile to actually get decent speeds, but that's because the MORE you upload, the FASTER you will advance on the queue list (it's the emule mechanism...). However, THAT information is stored on the other person's computer, so there's no way to trick it/mess it up.

One problem i've had in the past is my ISP banning emule ports/servers, so i could never connect, except to KAD. dunno, that screws it up a lot.