3.4 - 4.2 Without Breaking Anything Options

[7urrican]

my gf uses the ea fitness game every day on my pal 3.4 wii using usb loader gx. i really quite fancy a bit of monster hunter tri and metroid other m, but need the new cios's to play new games. i take it that they dont work on 3.4, so i need to update to system menu 4.2.

problem is i'm not sure how severe doing that is, and whether i lose the wonderful usb loader. bottom line is: gf will kill me if i balls up/brick her wii

so, what is the best way to update (have been reading good things about pimpmywii) and will i lose all my stuff?