Reduce effective frontal area and restrict underside airflow. Your suspension height data should also include lowering the overall ground clearance. On the concept, I've lowered the model ride height. Inexpensively, you could use Eibach lowering springs (Honda Civic?) Pro-Kit 25-30mm drop or Sportline kit for a deeper 30-50mm drop. Springs rates are kept reasonable & lowers your center of gravity. The additional weight of your boat tail will shift your CG towards the back, adjustable (adj. coilovers) ride height & dampening might be required. May be cost prohibitive.
You might also plan backup sensors with your longer & out of your line of sight boat tail dimensions. Take your pick.
Parking Sensor Backup Sensors Wireless Parking Sensor Kit