You need not really save it into a new model then reimport. If you group the whole structure you want to scale, and use the tape measure rescaling method while in the editing context of this group, it will only scale whatever is inside.
That's exactly the proper and idealuse of components. Also,to a limited extent,you can make changes to certain instances without affecting the others. These include
[list][]scaling
[]colouring
[*]moving and rotating (i.e.positioning and ligning anywhere)[list]
BUT in case you don't edit them just do these things "from outside" of the components.