The key thing is to make sure you get all the appropriate fluids changed:
6MT - Oil, Differential, Transmission
DCT - Oil, Differential
Based on various threads, people have experienced different levels of service at the 1,200 mile point.
In my opinion, if it isn't on the parts summary then they didn't do it. Just in case they try to tell you that something is part of shop supplies (e.g., transmission fluid).
I don't know that I have felt a difference in the "smoothness" of the car, but that is probably because there was a five week period between when I dropped the car off after ED and taking re-delivery. The service was completed proactively for me before I took re-delivery.
STOCK /// ED '11 E90 M3 : Space Grey/Fox Red/4MY : 2MT : ZPP : ZTP : 6NF : 6FL : 465 : 494 : 5AC : 639 : 655 : 752 ///
MODS /// Painted Reflectors : OEM Gloss Black Kidneys : VentureShield : 18" Winter Pkg ///