I put 150K + miles on a 540 and never had problems. I think one reason is a tip I picked up years ago. When you are coming up your final stretch before your garage, turn off the AC. This permits it (so I was told) to dry out a bit before you shut off the car and lessens the likelihood of the dreaded smell.
I replaced the micro filters perhaps once. The above technique seemed to work for me and will do it with the F10 also. If it ever stops snowing here in CO.
