Also there are problems putting in any kind of aftermarket head unit
that go beyond fitment.
If you have the L7 factory system you will also need a new amp because no
aftermarket head unit will work with that system.
Its reccamended that the original head unit be installed somewhere else in the
car to retain chimes , SOS , and PDC if you have it.
When doing repairs that require reprogramming or writing new software values to the modules in the car the old head unit must be connected for the BMW diagnostic computer (the one at the dealership ) to work.