The original blend file is the file I used to model the car and most of the modifiers are un-applied and most of the objects are separated. The simplified model has a lot of the modifiers applied and the similar meshes joined together to make it easier for animating, importing to game engines, or just being easier to understand.

This model was not specifically made for games, it was made for rendering, however, I leave you with a blend file with un-applied modifiers in which you can lower the polygons

I only unwrapped the mesh that needed textures so the interior is completely unwrapped but the exterior body panels are not

Yes it does, the interior was textured in substance painter, however, the car paint and other metals are just blender materials.