I optioned the DDC on my X2 with 19 inch wheels. Haven't received the car yet, but this is what I found after doing some research :
1. there are two settings. The 'sport' mode is apparently similar in stiffness to normal MSport suspension. The 'comfort' mode is a little softer.
2. these are selected from the existing switch that's used for selecting throttle response (ECO, COMFORT, SPORT). But if you want, I think you can unlink the suspension from the throttle through menu settings
3. the car will ride at MSport height (i.e. 10mm lower than stock)
4. The X2's DDC is a relatively simple version when compared to higher-end BMWs. The X2's DDC is just a valve component that moves on the shock, altering the flow of damping fluid/gas which then makes the damper firmer or softer. It does not dynamically react to actual road conditions and alter damper settings reactively, like the higher-end systems do.
The one downside was that I could not opt for the 20inch wheels...for reasons that the dealer and the so-called "Genius" still cannot provide!
Bottom line: go for it
