I have a 06 Z4MR with sat nav, I am wanting to update the 06 DVD and was wondering what is the best (and cheapest) way to do this. I have seen [link deleted] and was hoping someone on the forum may have used them and could let me know what they are like? I particularly like the idea of a custom start up screen. At £35 it seems to much of a bargain to be true. Can these DVD upgrades cause any permanent damage to my car? Am I just best off going to a main dealer and letting them take my pants down?