if its an auto you should be fine you have to be a bit more careful with a manual!
DMS automotive are supposed to be one of the best for the German cars BUT MSD in Blackpool who inverted the evolution chips are up there too. (I chose them for my fiesta!).

The BMW straight 6 diesel can when remapped develop more than enough torque to shorten the life of the standard gearbox! Therefore the car should be mapped with this in mind! Or upgrade the the gearbox too!

my 330d is no slouch my I have been in a couple of remapped BMW's and they were VERY quick!