I tunnel through my organization's proxy server to play WoW at work, and I get better latency (~200ms) compared to when I play at home (~300ms), which is most likely because the proxy server is in Singapore, although I don't know if I'm sitting on a dedicated pipe or whether it is leased from TMnut.

Why exactly are you tunneling, anyway? It won't do you much good if you're aiming for better latency, since WoW is unstable when played through tunneling.