Try to modell your car again. Try to start with a cube. The Polys Edge should be used to define the conture of your object.
Have a look at my attachment.

The "destroyed wireframes" will disapear, when you press "3" on your keyboard. 1,2 and 3 is for display detail.

Get involved with the use of crease edge tool, this will improve your modelling style when you use subdiv.

I've send more detailed information to your e-mail.

Andi