Car 4
Add-Surface-Surface. Place it like in the image at above left. In Top view, reshape the surface like a curve ( image above right).
Remember, to select an entire row of vertices select one and then, Shift-R keys one or twice. To select several rows, select a complete one press Shift, then select one point in another adjacent row and R key.
Select the two last rows. Erase them. Select the last. Extrude, again and again. Model them like in the image above right.
Extrude again several times and model to complete the bumper ( images above).
In Side view, Extrude, Move and Delete vertices to model the air intake.
The entire vehicule was made following the methods described above. When you have modelled all of the parts who compose half of the car Select and copy them. With the objects always selected, S key, don't move anything and X key, to mirror and Enter key to finish. Weld the two halfs by hand. Select 4 points and then Shift-f, and so on. I know, it's long...very long. It's my way.
But...this one it'll be better if you have many vertices in your object.
When you start to model one halve object, enter edit mode and align the first row of vertices, in Top or Front view, with the central axis line.
This way, when you'll mirror and join the object, you just need to enter Edit mode, Select all vertices and press the Rem Doubles button to weld the object.