I have a 2012 M Sport 535 and put on H&R springs 2 weeks ago... The drop is just like the pics of the 550's I've seen. I can post a pic if you like.... The ride is nice, though I do have the adaptive suspension which I am sure helps since I can still adjust it through the I-drive....
2012 535i M sport Pkg - HUD - Alpine White w/ Beige