Bump the lighting up, also try not to just focus on the car. Most of those shots are centered completely on the car, and zoomed in only on the car, not allowing the background to enhance the shots.
Also if you want to have more interesting/better shots, look up the rule of thirds, as it pertains to photography and art. That should give you an idea how to better plan out a shot.
For example, notice how the RUF shot looks better than the rest of them. That is because it contains more for the eye to follow, a distinct subject matter, a good background, and foreground. Whether planned or by accident, the shot has very good eye-movement, leading your eyes throughout the image, from the edge to the subject matter, then out through the background. Makes for a much better work of art than the other 4 shots. Also the shot is close to following the rule of thirds, an increase in brightness would most definitely make this a great shot. The only drawback to upping the brightness of this particular shot would be clarifying how flat the people look in the extreme foreground on the left.
Hope this info helps, and welcome to GTP.