Deleted your other post..nothing worse than two posts asking the same question as it devalues the answers.
The safest way, in my opinion, is right here http://www.wiihacks.com/recommended-...l-working.html
This guide will give you 4.1 but keep any Trucha and HBC. You may need to update or obtain IOS 56 and 57 to run those types of games though, but that's easy.
You might want to install bootmii as boot2 (if you can) before proceeding, just to be on the safest side of safe.