Arcade Series Edit
Spoilers can vastly improve the visual star rating of a vehicle in Need for Speed: Underground and Need for Speed: Underground 2 but high level carbon fibre rear spoilers have a higher star rating. Spoilers can also be equipped to a vehicle in Need for Speed: Most Wanted, Need for Speed: Carbon and Need for Speed: Undercover.
Simulation Series Edit
Spoilers can directly modify a vehicles's top speed and traction through the Autosculpt modifying of the spoiler. Spoilers can also be equipped to vehicles in Need for Speed: Shift and Shift 2 to increase a vehicle's aerodynamic capabilities. Carbon fibre rear spoilers don't have any effect on performance.