So i currently am using the 32 lb Accel injectors that came with the car when i bought it a few years ago. And I know that they are not helping my gas mileage so my question is if I went back to stock injectors, would I notice any kind of performance decrease with a bolt on car? And would gas milage increase?

 

If the PCM is programmed correctly for the current injector size, they are not hurting fuel mileage. Going back to the 24's will not change anything. If the PCM is not programmed with the correct injector size, they are wasting fuel.

On the other hand, there's nothing in your mod's list that requires 32# injectors, so they are not providing any benefit to the engine at all.