nope. this way you rescale the model.
- import original scania model first;
- import your own model (of a different size).
- create a box on original scania model matching the height on some well-defined measurement points (e.g. from rooftop down to the footstep). you need just one size to match, the height in this particular case
- create the same box for your own model on exactly the same measurement points. Notice, I don't suggest you to create a box of the cabin height, as models might have different 3D details on top or on bottom of cabin making measurement to be non-identical.
- read box height in object properties and write down the dimension matching on vertical object's axis.
- select all objects related to the new model and use modify\Scale tool to resize on all axes mode (toggle it in "Tab" window). Then type scaling value.
The scaling value for Scale tool is in percentage. 100 = no scale; 120 = 20% bigger, 75 = 25% smaller. In your case you should use a value: 100 * original_height / your_model_height
P.S. you can read box "height" straight after creating it, in an options flyout window; you can press "Esc" button to cancel creation, as you don't need the box object actually, just the measurement.