I tend to use the Action Replay application, but..dunno if it has that game. I would go on ahead and check if it does, but I don't have any gamecube controllers with me at the moment. ):
Since you have BootMii/boot2, you're likely better off with StartPatch.
Besides Waninkoko's 4.3 firmware updater, dunno about any other safe way to update to 4.3
I noticed when I have Waninkoko's 4.2 Firmware installed, backup discs appear on the disc channel as if it's reading the real game..when I updated to his 4.3 firmware, backup games stopped appearing in the Disc Channel.