The Comet S2, Comet S2 Cabrio, Itali RSX, and X80 Proto are all cars in GTA Online that don't quite work as they should regarding their spoilers.
YouTuber Broughy1322 recently posted an interesting video documenting these vehicles' strange behavior. Spoilers affect wheel downforce, and it's good to have a higher value. For example, some vehicles with an active spoiler would have a value of 0.07 with a custom spoiler.
In the case of the first three vehicles, their overall performance is lower than it should be. They are bizarrely stuck with a maximum wheel downforce of 0.035, equivalent to an average car with no spoiler.
Hence, they don't receive the usual advantages a car gets for having a spoiler (despite it being clearly visible on the vehicles).
As for the X80 Proto, its performance will either work as it should or not at all. That factor depends on where the player is on the map.
Some active spoilers in GTA Online don't work properly (Itali RSX, Comet S2, Comet S2 Cabrio, and X80 Proto)
The above video is from Broughy1322, who did a superb job pointing out these inconsistencies. In GTA Online, there are five types of downforce mechanics, with all of these "broken" cars utilizing the active spoiler mechanics. Having an active spoiler overrides spoiler upgrade bonuses and downforce modifiers.
Remember, a standard car with no spoiler would have a wheel downforce value of 0.035, whereas one with a spoiler would have 0.07 or higher. Three notable cars with active spoilers are stuck with the 0.035 value, which isn't ideal:
- Comet S2
- Comet S2 Cabrio
- Itali RSX
That value affects their traction and top speed, which means those three cars could be doing better if they worked properly.
It is unknown why these specific vehicles have an incorrect wheel downforce value in GTA Online. They weren't hit by any nerfs, so one can only speculate why these specific vehicles have the lower wheel downforce value. The Itali RSX, in particular, stands out given it already has a remarkable performance for a Sports car.
If the Itali RSX had the 0.07 wheel downforce value like other cars with active spoilers had, it would be even more dominant for races than now. Sadly, it and the two Comet S2 vehicles are stuck with the lower value of 0.035.
The X80 Proto has a different problem in GTA Online altogether. Its wheel downforce value is supposed to be 0.07 when one of its flaps is at its maximum angle. However, the flaps only work as they should based on where the player is on the map.
Essentially, GTA Online players on the right side of the map will receive the full benefit when turning left. However, turning right won't give them the 0.07 wheel downforce value, making the turn feel less fluid.
It's the same deal with the left side of the map, except in reverse. If GTA Online players are on the left side of the map and turn right, the X80 Proto will work as intended. Predictably, turning left on the left side of the map doesn't work correctly.