What are the only mods that you are allowed to do to your Wii for it to still be legal to use for speed running SMS?

You're allowed to softmod with pretty much anything you want as long as it doesn't increase performance which would speed up loading times in your runs. You can even install nintendont and us it to practice even though it speeds up loads when you use it to load the game as long as your actual runs are on disc through either the disc channel or a loader that does not increase performance like swiss.

Ok

is wii flow a loader that doesnt increase speeds that I can use to run

From what I could find online, WiiFlow can't run GC games directly, so it depends which GC loader you give it in the settings

i mean gecko os is what most ppl use to load disc for running the actual game

I have nintendont rn but what loader would be fine for gc

if u mean wii then in the rules there should be a link to gecko os

i had this same issue before. i'm pretty sure if you're using any loader outside of the disc channel it does speed up load times, so you can't use unofficial discs or load the ROM from usb/sd.

you can always practise and go for runs, just can't submit them to the leaderboards. if you got some money to spend, sunshine discs are dropping in price since 3D All-Stars was released so you should be able to find them pretty cheap on ebay. i bought my NTSC-J one for like 20 euro.

ah ok thanks for the info guys ill look into the disc stuff :)

@whichevermirror: The loader isn't the problem there, loading from USB/SD is much faster than loading from a disc, but loading an official disc through loaders like Gecko OS or Swiss is fine