I bought 2 used 265/35/18 Run flats to replace on the rear when I sell the car since I learned to drifted on the original Run flats. I was wondering the same as well. I want to use the stock wheels and I have the staggered setup. I was going to take a wheel and tire down to the tire shop and have it mounted with no balance or anything just to see if it would fit.
2015 M235i - Estoril Blue - 6 speed - Black Lather - Cold Weather Package - Premium Package - Harmon/Kardon Premium sound