I have owned 3 bmw's with RFT including an extra set of snow tires. On my last car I had to replace a severely damaged rim. I have had my rims tested several times and fairly commom to be slightly out of round which do not affect balancing. Rims that are not too bent can be straightened for under $200-
Two additional consideration is that the newest (3rd generation rft) have much softer sidewalls so less ikely to bend rims on pot holes, but on the negative side would a dealer check rims on return of a leased vehicle and try to charge for abnormal wear and tear?
2007 335xi (ED 5/10/07, Redelivery 7/12/07)
2010 335i-xdrive (ED 10/19/09, Redelivery 12/30/09)
2013 335i xDrive (ED 9/15/12), Redelivery 11/23/12) mineral grey
2014 X1 xDrive28 (ED Scheduled 5/13/13)