Bit torrent is new tech if I remember. Also if I was a firewall and I that much information flying, I would be concerned
Doesn't bit Torrent create multiple session with whomever is downloading all that file, and getting everyone to download/upload it at the same time?
Personally I would skip zone alarm and just get a router...I don't like software firewalls at all.
It's arguable that Firewalls create latency (not exactly slowing down your connection, but just the responsiveness) but it would to such a low and unnoticable amount I wouldn't care for it.