Well, you may not remember Kazaa Lite. But, basically, all you would need to do is unpack the installer with a tool that creates installer programs. You would basically need to decompress it, strip out all the adware or anything else you didn't want, create a new installer and you're done!
Kazaa lite had a lot of other tweaks and hacks to the exe, which I assumed used some sort of decompiler to essentially "crack" it and modify it in certain ways. Then, along with registry patches and changes to other libraries it used made some fundamental changes to how it worked and connected to the network.
Someone wouldn't need to do this for uTorrent if they just wanted vanilla uTorrent and nothing else, but the possibilities exist.
