Are there any router-side settings that might improve my SSBB performance?
Note: I'm switching back to cable from DSL, so that will most certainly help.
There's a few things you can do, and won't hurt to try. Other wireless traffic on your router and the quality of your opponents' connections (they should do similar router tweaking as well) including number of players and respective distances, have the most impact on your experience.
This is largely based on Nintendo's wi-fi faq on their help page:
1. Allow an excessive range if IPs to be mapped (at least 10 values from your other wireless devices). Assign your Wii a static IP address toward the end of that range. In my case, I have a range of *.1 to *.25. The computers in my household end up usually in *.2 or *.3, up to *.5 typically. My Wii is at *.20
2. In the router, set your new Wii IP address to "UDP only", as opposed to TCP/IP, or TCP only.
3. Allow "Port-Forwarding" on your Wii IP address for the entire range, 1 to 65500, something like that.
4. Set your router's wireless/broadcast channel to the extremes like 1 or 11. If you have a lot of neighbors with wireless networks, they might be doing the same trick, so use 2 or 10.
5. Manually set this same IP address (and related Gateway info) under your Wii Settings/Console.
6. Tells your Brawl friends to fix their internets as well.
I use these settings with a LAN Adapter and on Comcast's lowest-end (384kbps upload) service plan. I have little to complain about in 4p matches (Continental U.S.), and other forumers who've joined me would agree.