I have whatever spec was, I think 38 is accurate.
Mine came with the 21" wheels, sport seats, sun roof, etc so should be pretty much the same weight and driving dynamic as the competition. No spare, but I did put that fancy plug kit in the car. I weight about 220lbs and I had some other misc stuff like 2 cases of dog food and some clothes, etc.
I doubt there is much difference in unsprung weight with the smaller wheels since the overall heights are the same. I think I saw a post where someone weighed 20" snow setup vs 21 factory wheels and they were close to the same.
Either way this car is getting fun the more I get used to it. I had a 330i try to run me from a light today
