Re:Easiest way: Raise QoS of OTHER traffic. (Score 2, Informative)

>d) start using TCP-vegas on the router: Add the following custom script for boot:

That won't do much good on the router. Your router is a layer 3 device and (except for packet classification) only looks at the IP header. TCP congestion control is layer 4 and operates at each end of your TCP connection. This is a good idea if your P2P client is running on a Linux box, however. But do the config on that box, not the router.