Originally Posted by HatchVX
it does need a wing, but if there is one on there it should be adjustable.
In a windtunnel, a spoiler in that location probably wouldn't get enough airflow at any speed to warrant adjustability.
Remember, a step in the back of the car like that creates horrible aerodynamic drag issues by creating an area of low pressure behind the cab. It's possible that this added drag will negate the few pounds of weight savings it will offer.