Hey, youre new here..... Welcome!!!
I know that some aftermarket company makes struts for your model (KYB if im not mistaken).... One of the moderators (kcnewell) did it to his car, and they were like 60-80 a piece...... The thing is, his was a 91, so that is different........
I also heard that you can put the SLS model struts into the STS (their the same, but the SLS doesnt have CVRSS), but again, I dont know for sure.....
But I am pretty sure (94%

) that there is a passive strut for your car.......