that tool is use only for looking in GT3(GT4).vol file (see directories and files) and extract single files from that
but not possible is repack that file or changes in the programmcode
i think is a job for hardcore programmers
would people that are saying 'my fav track aint there' because in that list theres only about 20 - 40 tracks (files) and in the full game there is going to be 100 tracks, so hope that boosts your hopes
Of course it's not the full list, PD have confirmed 100 tracks, expect it to be 50 with reverse variants, but theres no where near as many in that list.