In the rear I started with Griggs subframe connectors, then installed BBK lowering springs and Koni reds.  This made a difference, mostly in looks, but the Suspension Techniques sway bars I added next helped the car lean less in the turns.  The Griggs panhard bar and torque arm were installed later, which help lower the roll center and give the car better bite.  With the torque arm and panhard bar installed, you remove the upper control arms and quad shocks.  The stock parts perform the same function, although they don't do nearly as good a job.  The panhard bar eliminates most of the side to side movement by positively locating the chassis to the differential.  Since the upper control arms bind as the car leans, they act almost like a spring, providing resistance and adding to the spring rate.  With the torque arm and the upper control arms removed, you have to use a stiffer spring rate to compensate, so I replaced the BBK rear springs with stiffer Griggs springs.  I just updated the rear suspension to Maximum Motorsports Bilstein coil-over kit and I love it!  My car always sat a little uneven, and it also had a problem bottoming out with Griggs' stiffest rear spring set (350 lbs/in).  I used 225 lb/in coil-over springs, which are actually stiffer due to the mechanics of where the springs sit on the suspension arc.  It feels better, and I was able to raise the rear just enough to be comfortable, to sit evenly and to look better.  Plus, the Bilstein shocks are top of the line and have excellent ride quality.  Check out the new pictures of the torque arm and the panhard bar, they really make the rear end feel rock solid!  You can feel the difference the most in the turns, since the power of my car overwhelms the street tires even with the torque arm off the line.  For pictures of the coil-over installation with before and after pictures, click here.