I have the TFS self-adjusting KYB struts in the rear. I also have poly bushings for the torque strut, the tri-links, and the sway bar bushings. My Fiero had about 58K on it when these changes were made. My tri-links looked OK, until they were removed, at which point the bushings turned to dust. The shocks were apparently bad. Anyway, everything is nice and tight, now. Mine is not lowered. When I get time, I'll replace the control arms.
Before the swap, when making a left turn from a decline to a flat surface, the back end seemed to hop around. No more.