Well, put it this way... to host a DX9 game doesn't take very much. I've actually got a dedicated server up and running to see if any bugs show up over time. We did some load testing and it never really went over 30% supporting 4 users (some of our vehicles still cause funny physics errors which we're fixing) and typically hovered around 10% load. My uber-leet server is a dual P3-1ghz machine with 1.5 GB of RAM. bandwidth was around 3kbps per user so hosting a 32 player game isn't a problem. Dialup gaming is, not impossible, bt extreemly unlikely.
When DX10 is turned on, that same server, instead of peaking at 30% pegs both CPU's at 100% and has physics time going backwards cause it can't keep up. Bandwidth spikes to, as I said 200-500kbps during DX10 events. With a C2D or C2Q powering the server it's not a big deal on a LAN to run the fully destructable environment, but over the internet it might be pretty rouugh playing since, if you think about this, the server has to have as much bandwidth as the sum of the player's internet connections when the environment is getting torn apart, and lets face it, that's what mechs do..