I skimmed through the thread in your second link (didn't really look at the first one much). Towards the end folks are complaining about Voice searches and other apps the use the microphone not working. So it may not be a good idea to flash one of those zips.
If you choose to make the changes manually, you might (!) be OK with skipping the mods that have to do with the mic.
I'd strongly recommend making a backup of the two files before modifying them so that you can easily revert back in case something goes wrong.
Alternately there is this, which I have never used only read about.