Flyyair Struts (Used) fits a 2015-2021 Subaru Wrx. Comes with all 4 struts.
The bags themself have no wear on them and were used for a year. Never had any problems, just wanted coilovers instead.
All you would need to buy is the air management for a complete setup.
Do note that the front struts are slotted for camber purposes. That is the reason why they are listed for a good price. Never had any problems, as long as you tighten up the bolt as needed.