Again, it's not at the top of the list, but it certainly serves a better purpose than the front one.
When I braced the rear of my SVT, I felt a slight improvement in stability from the rear end. BUT you have to consider the suspension I was running... a full race LEDA coilover setup. On anything softer the benefits wouldn't be as noticeable.
It did help a lot with reducing creaks and rattles back there, especially when driving diagonal over speed bumps or coming into a driveway... proof of it's action in making things more solid.
Again, other things do come first.
