IMHO you waste to much polys, eg. you made a hole for the fog light and the lower air vent, but the grill is just a texture. so think about the details, WHY waste polys for small parts you may only see in close ups.
another example the 5th wheel on the back, you can save some polys on the underside of the wheel, (reduce some) simply coz you won’t see the underside that often, maybe only if the car crash
I know it takes time to see where you can save polys, but think good about where to put details and where not, and why not.
Another point is to spend more polys in the key features of that car (whats in focus?)
Zoom out a litle, you will see many of your polygones are unseen from distance.
I only whould use a polygone for the third brake light, if I have to use Vertex Coloring (for a light effect).
I’m noit sure if you understand what I try to say. It would be better to make a overpaint for you, but I do not have time for that :\