Just did a valve adjust on a 03 m3 today.
I also replaced the vanos unit for a " vanos inlet end position fault."
As for taking the m3 to the dealer I am not so sure about that. Usually all you end up really getting is a new valve cover gasket. (if you are lucky).
I ACTUALLY do the adjustment. Furthermore, I hand lap the valve shims to set the clearance as close to perfect as possible.
The dealer doesn't do this. Good luck even getting a "real" adjustment from the dealer.
