What can bring an improvement is the management of the airflow around the edges and over the body.
For example using little plates on the front left and right corner to direct the air upwards (like DTM) and using little long vertical planes on the left and right side of the hood to prevent the air from slipping off the hood to the sides of the body. Important is also how the air leaves the body behind. Sharp edges on the trunk- and rear lights- corners are very important for reduced drag. Overall you should achieve a low pressure area under your car.
All these tweaks will only work at speeds +25 Km/h.
AE / Reedy / RSD