Rear Sway Bar?

Pretty much any new vehicle has both front and rear stabilizer bars. What people overlook is even if its still a unibody is has stiffening rails front to rear. That's so the 2 stabilizer bars dont twist the unibody chassis so bad that the dang doors dont close. Look at Mustang, even a RAV4. A rear bar isn't as stong as front bar. It's just a little something more when needed. For our old a-bodies... wedont have radial tuned suspension, coil springs, struts, etc... Most of them didn't even have a front stabilizer bar. Some did get a front bar but it wasn't all that. Aftermarket offers front bars that are much more than OEM. Some police cars (later model diplomats and others) got rear bars but again its a smaller/weaker bar. Those still didn't handle like todays vehicles.
Bottom line, if you'll add a rear bar, add subframe connectors.