I've never heard of manual port forwarding working without a static ip. After all port forwarding is based around the ip. But if the BT is something different, then it means it's a lot better than all other devices that are port forwarded. The reason being that normally as soon as one's ip changes (dynamic ip) then the port forwarding process will no longer work. But as suggested I'm happy to learn something new. And it proves the experts at portforward.com wrong. lol
I had an experienced user of p2p (not gnutella) suggest to me it's more effective to do a separate port forward for each of TCP & UDP, rather than do a single one for both. Apparently puts less stress on the device or something to that effect. Thus I do mine that way.