Vehicle Modeling

I almost finish modeling my Lamborghini.I wanted to use NURBS at the beginning, but due to the fact that we only have one week to finish modeling, so my professor suggests me using polygons. Well, I still outlined the contour of the car. I used lots of techniques that I have learned from a tutorial, which the instructor used CV curves and Create Polygon tool. Right now, the major issue is that I have to keep its poly-counts under 5,000 faces, and the same time keep as many details as I can. I eliminated lots of its faces now,but the surface of the car is not as smooth, so I guess I have to use the high-poly version and bake its normals on the low-poly version. Here are some screenshots of my car: