@tig said:
If you have some Scenes when you want 'solid' people/cars and others where you want 'wireframe' use Layers and Scene-tabs.
Make two Layers named SOLID and WIREF.
Your people/cars should be components.
Put them all on the SOLID layer.
Now make a copy of all of them and put those on the WIREF layer.
Switch the SOLID layer off...
Select all of the people/cars [on WIREF] and use make unique on these - this way you keep a 'solid' set unchanged.
Edit each person/car component in turn.
Select all faces [use one of the selection-tools available] and delete them [a quick way is to use Wireframe view mode, select all edges by fence, Edit>Cut so the faces auto-delete and them immediately Edit>PasteInPlace so only the edges are left - go out of Wireframe mode to check they've gone!].
Use 'Entity Info' on these selected edges to stop them casting shadows etc and then you have what you need.
By toggling the two layers ON/OFF you can have solid/wireframe people/cars in different Scene-tabs...
If you move one need to remember to move the other - easy done if both layers are temporarily on while you edit...
The awesome trick worked 
thanks indeed ! 
