NSMB is 4.1.
NSMB also has an updated IOS that you'd need.
Softmodding and USB HDD, or WODE in the near future is much more convenient. I can't imagine how I ever managed before having all my games in a little black box next to my Wii.
You need cIOS38rev14 and USB Loader GX, Wiiflow, Coverfloader etc etc. They all do the same, they just look different.