this is from the HUDY Truggy Setup Guide:
EFFECTS OF REAR WING ADJUSTMENT
WING POSITION/ANGLE CHARACTERISTICS
Higher • Increases stability at higher speeds
Lower • Increases stability at lower speeds
Forward • Decreases rear traction
Rearward • Increases rear traction
Flatter angle • Level jumping or nose-diving
Steeper angle • Increases traction at higher speeds
• Less nose-diving