FIRST THING TO DO!!! use banner bomb to run the hackmii installer. Then go into bootmii and do a nand backup. Do that first so no matter how badly you mess it up then you can always go back to fresh (in some cases requires a infectus to restore it).
Then go about and read some guides.
I personally recommend to stick with SM 4.1 because 4.2 has too many issues and it's not worth the upgrade.
Since you are on 3.1, you wii is definately old enough to install bootmii as boot2 which is the best thing since sliced bread, and your wii has a trucha bugged ios.
First use install waninkoko's cIOS 38 rev 14 from HERE
, and then use waninkoko's 4.0 firmware upgrader and then his 4.1 firmware upgrader.
From there the possibilities are endless. As long as you have bootmii as boot2 and a nand backup then you are safe (or at least recoverable). There are many guides on this forum to get you what you want.