Its annoys me how people can start with a spline mesh, when you could take that spline mesh and in 20 minutes turn it into a car.
Its not bad, however there are problems, your front door is attaching to the window rim, this means that your bonet should extend further to attach to it rather than the door, which means your seem is in the wrong place. Also the window rim would attach to the front of the car aswell as the side.
Your bonet seems slightly too flat, and also the part of the bonet facing the back of the car should have a part which dips down, which will be where the window cleaners are held.
Heres a picture, i understand it is a different model, and that you arent near finishing, but I feel it is nice to get everything accurate even before you touch it up.
On your last picture, above the wheel arch there is a slight lump, this tells me that your lower polygon base model is too high polygon that you cant control it enough.
I also reccomend making the roof before you make the doors, and working down from the roof.
Nice work so far thoough.