Firstly, if you put the torrent box on a dmz nic, then you don't have to worry about any issues with the linksys wireless router.
Secondly, I like to keep my wireless traffic separate from my wired. That way I can handle it differently if I want, and if someone manages to crack my encryption, they can't get to my wired machines.
Thirdly, if the torrent box is on it's own nic, then you know exactly what it's doing, and don't have any extraneous traffic to deal with.