Here's what I wrote in another post, a little more technical :
the point that should be made is that EDC is dynamic and constantly changing the compression and rebound settings of the dampers. A non-EDC car has dampers that have fixed compression and rebound settings. This is why you would buy EDC, and accordingly one really shouldn't be trying to compare the performance of an EDC car with that of one without - they are two different animals in a sense.
There are not 3 distinct compression/rebound settings for the dampers because there are 3 "modes" in EDC, which I would guess some people might think as well (I think there are other car systems out there like that).
As I understand it :
1) Normal mode means that EDC is doing it's "regular" thing of automatically and constantly adjusting the dampers according to your driving style, cornering, braking, road surface, etc. - this of course means that there is no fixed settings to compare with a non-EDC car.
2) Sport mode is limiting them always to a certain specified range of travel which results in a stiffer ride because they are not moving up and down as much - this would relate most closely to a non-EDC car, though I guess only BMW engineers and aftermarket suspension tuners would really know.
3) Comfort mode (which I agree may be more of a marketing thing) supposedly allows the dampers to have a lot of freedom in their travel, but calls them to attention at certain times (which to me sounds pretty much like the Normal mode) but I'm assuming is a little more lenient.
Here are two good links on it -
http://www.bmw.com/com/en/insights/t...damper_control
http://www.bmwheaven.com/content/view/136/5/1/3/