Good work buddy !
Can you post a clay + spline cage render, I think there are some strange reflection on your car.
I also think your hubcap’s material is really strange, you may have to find something which works better.
The license plate looks really flat, think about adding a bump map.
On the modeling part there is some mistakes like missing hard angles which I think are really important to give some character to the car. (open the image in big in your browser so you can follow along)
For the rear view:
The two green edges at the rear : you put hard edges which doesn’t exist
Black circle : the position of the logo is wrong, it’s just under the hard edge of the car boot.
There are some wrong shape : the headlight for example, I put two circles were the angles are smooth instead of hard. Same thing for the air inlet in blue. The angle at the bottom has to be hard and the shape is wrong. The hard line need to finish its course just above the little headlight and not above the license plate. Same thing for the window, you need to have a hard angle here.
I think the air inlet on the side is wrongly placed. It’s definitely larger and closer to the door
For the front view
In blue : there are missing hard line (I don’t know if you didn’t did it or if the quality of the render is too poor to see them)
Red : wrong shapes, missing hard angles.
Pink : the underbody doesn’t go that far you need to remove that
Green : Some grid are missing there
Hope it can help, a high quality clay render, can really help us to see the shape and help you to improve your work. There is no reason for you to start rendering because it’s really misleading as the modelling process is not finished.