This article may have been up a while, but there is a big difference between a spoiler and and wing, which you have not covered.
A spoiler is an aerodynamic aid but it has a totally different function than a wing. A spoiler does as its name states, and spoils the air flow over a vehicle of certain shapes and prevents the whole car from turning into a wing due to its shape. Spoilers do generate some downforce, but not much.
A wing, on the other hand, is what is found on high performance cars and generates much more downforce than a spoiler.
An example of the airflow between both can be found on Google images by typing spoiler vs wing and viewing the third image.
The top image is a spoiler the bottom a wing and you can see the difference between the air flows by the blue lines behind the cars.
BEng Motorsport Engineering student.