Yeah all you need is NitroExplorer2b and PPTXT and you're set. Main files are located in a/0/0/2 and story files are in a/0/0/3.
Extract 2 and 3 with NitroExplorer2b, edit them with PPTXT (Always remember to File>Write to Narc) then re-inject them back into the game with NitroExplorer2b again... and test
P.S.
Download the source from the githubs, PPTXT has an Import all from files option
P.P.S.
Anyone who can't wait for a v2.1 do this cause my laptop is crapping out and failing to show japanese text properly out of nowhere so I really can't do much right now.