These rear braces help strengthen between the strut towers on the rear of the z31 greatly reducing flex in the rear of the chassis. Unlike the others on the market that are multi piece design and still allow flex, these don't allow that problem.
The baseplates are cnc cut from 1/4" to help clear the raised lip on the strut towers, the rest is DOM tubing and fully tig welded. They also alow for ample room for coilover dampening adjustment.
These will require notching of the rear plastic and are a 100% bolt on.