Hi, I intend to do runs of NSMBW, am I allowed to do it on a modded Wii U? Softmod/Homebrew only, no overclock. I have a legit NSMBW disc. Is this allowed?

As long as you load the game through your disc, its perfectly fine to have a modded console.

Cool

I don't think any top level runner has ever tried doing that, so it's not something we've ever really considered. Adding a time penalty wouldn't be an option either due to the way that loads in this game work.