so I decided to replace it, but I want to replace them with used ones, its cheaper,so can somebody tell me what is the exact name for it or part number? is it air suspension shocks?

 

got it fixed with a repair kit, but dealership refuse to reset the height, they saying that its not included in 300$ labor, my front still sits low and my back is really high, are they bluffing or I actually have to pay extra?