The only way I know how to limit it,
is to put a really crap file in the incoming shared directory.
Set it's priority to release,
then set all the other files you are downloading at the moment to very low priority,
and then move the files out of incoming as you download them. You still are going to upload, but it shouldn't be that much..

And the best kinds of files to upload are like foreign language programs, media, etc...

Free operating systems like Linux, and so on.