I think what Red Dog meant was the "split" command in edit object. This will break up the model into pieces, reference are the different materials used in the scene. May be a bit difficult in the dystopia items. What you could try as well is to use boolean functions to cut the parts off that you do not want - should work too.

Regarding other models than the ones that are provided directly in Vue native format work fine as long as they have two thibgs provided. #1 the object is separated in pieces so that you can apply your own materials to these parts. Or #2 minimum the model already has different materials applied to the parts. Then it is an easy practice to exchange these (basic) materials with the ones you want.

One day your ship comes in - but you're at the airport.