bah spelling owns me.
Just go to a shop that deals with BMW point to the wheel you like and they will help you with everything else.
Generally when you have less sidewall the gap between the tire and the fender looks larger, so lots of people opt to lower the car too, this will make the whole car look better, but on a BMW this is not cheap to do properly.
Good luck, ps go to
www.bimmerforums.com and look in the wheels section, and post up your questions there.