NextGen Vehicle: Police Cruiser

I decided to join you in this contest. Never modeled something low-poly, that's why it's really interesting task for me. I'm not confident that I can do it though.
I want to create police cruiser. It was inspired by 1960's police cars. Here's my progress so far:


Looking really good, but i think you could do the same results if you lose a few polys on roof and hood. would save a few polys for the rest of the car. :)