I'll have to play around with the mic gain settings on a few drives before I permanently move it to the weather strip or headlining, it didn't seem to like the wind noise before when the roof is down.
I wouldn't worry about moving it back, on early Z4s the mic was by the rear view mirror and the sound quality was poor. On the facelift it was moved to the top of the steering column which works far better, so I'd stick with that.