Andy: initially we tried to push the right side up (the right was lower than the left) by bending the hangar, but that seemed unrealistic. Instead he lowered the left side to sit level with the right. Unfortunately I never asked exactly how my shop did it, and I doubt they would remember by now.
See if you can lower the left side; it should be a lot easier.
David: here is a comparison of the stock Altima on the left, with Eibach springs on the right.
http://i61.photobucket.com/albums/h78/l ... mpare1.jpg. If you want to go lower than that, you should invest in coilovers like BC or Tein. With coilovers, it's not the spring length that determines how low it sits, but the strut that can be lengthened or shortened.