To install the LW by Jum, simply drag the folder called "Limewire" onto your harddrive. It's called a Dragndrop install, you'll see them becoming more common in OS X.

The bandwith slider thing can work. Yes, disabling ultrapeer will help reduce your downloading bandwith very much, and your uploading to a certain extent. However, excluding content, the ultrapeers with the new compression only do about 8k/s upstream and downstream in messages. That's not very much on a high speed connection.

Yeah, after about 48 hours, I get a spinning wheel of death too.

Limewire in no way, shape or form condones the illegal downloading of copyrighted programs. I assume, when you (carelessly) mentioned some of the content you downloaded, that you held the license to it, or had purchased it previously.

Browsing hosts. I suppose one could log the IP address of the host, connect to the host, and if successful (they might not have an open slot) search for a file you know they have, and then browse.