Does it seem to be the front end that does the sway?
The most likley cause is the stabilizer bar bushings. They can be inspected easiest with the car in the air to see if they have shifted and the bar is off center.
Tha that combined with a good 4 wheel alignment (the rear camber and toe can be adjusted) is really about all we see with these cars that cause the sway.
I recommend a GOOD front end alignment specialist to do the alignment, because ALOT of your "average front end alignments" are done too quickley and the rear gets over looked many times.
If you have further questions on this, please feel free to reply.
Its possible, because its hard to tell sometime, but the front has a stabilizer with bushings as well. And like i mentioned, combined with a good 4 wheel alignment, should get you all straightened out (your car i mean) :-)