A quick search from our sponsor shows the struts to be about $300 vs $100 for a sphere. Each.

Tire cupping has nothing to do with shocks or struts. Tire cupping is a product of alignment or ride height. SLS does control ride height, but the pump and level control valve are responsible for ride height, not the struts or spheres. Even on a non SLS car, the shocks have NOTHING to do with ride height, unless they are air shocks or have their own springs (we used to call them over riders, not sure they exist anymore).