Also consider to support dexyfex on his work on CodeWalker. He doing it for free but work how its done its impressive. Without CodeWalker many things in modding would be impossible! Thanks to CodeWalker we are able to edit/create many files that are not supported by OpenIV
All is up to you.

Also consider to support OpenIV team on their work. OpenIV was first tool that enabled doors to moding. Many modders using it every day for importing/exporting models.
All is up to you.

Also consider to support GiZz on his work. GiZz created gtautil -usefull tool that support e.g. ymap, ytyp, ymt ect. Advanced possibilities with edition MLOs ytyps and much more. Also GiZz is working on plugin for Blender that will support import/export gta files.
All is up to you.