If you're using .torrent files, you need to make utorrent the
default app for them: hit Cmd+i on a .torrent file, go to the "Open
with" section, select the torrent client you want to use on the
dropdown menu (if it doesn't appear, click "Other" and search for
it in your Applications folder) and click the "Change all" button.
Then, if you click any .torrent file it should open this app, and
TVShows will also trigger it.
If you're using magnets, I'm afraid there is no system setting
for handling magnets. Transmission has its own "use Transmission
for magnet links" option, but I don't know if utorrent has it. If
it doesn't, you can use RCDefaultApp,
it will let you choose the default app for pretty much