Downloading files in little pieces is good for large files from multiple sources, but it does have a drawback. Another peer can slip a request between your pieces and steal your slot!!!

I can't tell you how many times I've been downloading from a single slow source, everything fine, when suddenly the status changes to "waiting in line".

Splitting up files should be disabled for single source downloads, or at least add a tracking number so that peers in the middle of a download aren't kicked to the curb.