I don't think they make a camber kit for the rear of our cars. I think the closest we can get is those different bolts that change camber. I did notice that both the front and rear of my 200 seems to have some negative camber. I'm running agx with S.T springs.
I like the s/t springs a lot. They lowered the car about 2 inches in front, and a little less in back. The car looks tastefully lowered, and the best part, it doesn't have a raked look. (lower front/higher rear).
Sounds like these springs are a little softer than the eibach springs. Though I never bottom out. Compared to my 92 SER with tokico springs/kyb dampers, these are a joy!
When combined with the AGX, they accent each other. Plus you can set them soft for road trips, and set it firm for track day!
Hope this helps you decide on which is best for you.