We have had this discussion on the Triumph forum in the past. When you see all the adverts of a convertible car with the roof down, the windows are always also down Why? because it looked better I always drive with the windows down when i have the roof down. But so many people drive with them up, I have tested this with the triumph and it has been proven that there is less wind buffing with the windows down. I have not had the Z3 for long enough to experiment as yet to see what is better. so boys and girls what are your thoughts?