Ideally you want part groups to be under 30k verts to optimize it for lag. The most I would go is 60k but try to be under that. If you want a part to be a store option it will have to be separate. Do your best to name each part group and add a separate material to anything you want a different color and or material type. Youtube tutorials you can learn quite a bit like lambo mods has. I'm starting to do some on my channel so feel free to sub and see what I come up with. https://www.youtube.com/@expendable_dirk/playlists