If you do not need a rendering with material, the organization of materials is made to work without any textures.
I mean, for example, chrome is a unique material, the bodywork too, just like leather and plastics.
If you want something very light, just remove all the textures.
Only a few small details are not modeled in polygons and this will not hinder the aesthetics of the vehicle.
It is always difficult to find the right balance to configure an object for sale, the uses can be very very varied.
My logic is to tell me that it is better that I put a maximum of things and that the users will be able to remove what they do not need .. it is easier to remove than to add things;)
In any case, if you need technical advice, do not hesitate, I have some background in FX and production :)