The Twilight Hack works on any Wii up to 3.4.
Even with 4.0 you can use Bannerbomb or BootMii.
Bannerbomb and BootMii work on any Wii (Not the absolute newest released Wii's though iirc) but are the only way to get it on 4.0.
With Bannerbomb you don't even need Twilight Princess to run the Twilight Hack for 3.4
Though 3.2 is the "best" system menu to use for Homebrew, due to the fact that it can run any application (later system menus prevent some really cool stuff from working). But if all you want is to get into Brawl+ then don't worry about downgrading, everything will work fine on 3.4.
Head over to Wiibrew.org and just look up anyone of those, and you will be running the HBC in no time.