The door

The next modeling task is to create the doors. Because we did the 'instance trick' we only need to model one. The approach is similar to the one used in modeling other parts. Therefore we also decided to show many images and little text for this object. Make all objects except the Mudguard Wireframe Invisible. Take a side view. Then start with duplicating the Mudguard and rename the new object to 'Door_right'. In Face Edit mode, remove all unneeded faces, so you end up with an edge of faces shaped in the profile of the door. Switch to Edge Edit mode and start adding new faces and then use Point Edit to modify the shape to match the blueprint.

 
Mudguard duplicated and all unneeded faces deleted

New faces created, points edited and moved to match the blueprint in side view.

When the door is modeled in side view, go to a top view to do more point editing and make sure the object matches the blueprint.

Select a vertical row of points and use the red handle to scale the points in position

To model the air inlet, we move and bend the lower edges a little inward (see next image)

Lower edges moved and bent inward

Then it's time to set the edges to the desired sharpness. Select the edges as shown in the next image, open the Property window and set these edges to 'Sharp':

Select these edges and set Edge Sharpness value to Sharp

And to finish the door modeling, select the edges as shown in the next image and set the Edge Sharpness for the upper ones to 'Semi Sharp' and the lower ones to 'Sharp'. That should do the trick for the doors! When done, save your work.

Upper selected edges are semi sharp; the lower edges are sharp...

And that leaves us with showing you the results so far:

The hierarchy at this point

We are getting somewhere now...