I would say you are good for a while with just oil changes and anything that may come up. Another easy thing and recommended is to remove the vanos solenoids, clean them with MAF cleaner, blow them clear with compressed air and then swap them (intake to exaust, and visa versa).
See this DIY:
http://www.e90post.com/forums/showthread.php?t=486201
The guy was putting in new ones, but the work is the same. Only thing you need to remove is the intake snorkle, the engine cover can stay on.