The other piece of information you'll require is the site at which the X3 is being manufactured.
Audi's have notoriously hard paint so being a Europian make doesn't necessariliy mean a finish is hard or soft.
With X3 being a new vehicle, probably not a lot of people have had an opportunity to detail them yet. However, if you can find out which other BMWs are manufactured at that plant, that will help you get a baseline whether its a soft or hard clear that used.
The other thing is, most products work with every type of finish. It's more about the user and condition of the paint that effect waxes.
For polishes, that changes slightly as some polishes do work better on harder finishes.
Paco