From what I have seen the base wheel is one thickness, and the sport package wheel and the M sport wheel are the same thickness.
I am not sure now but in 2011 when I got my car there were non sport, sport and M sport options. The only difference I could tell between the sport and m sport wheels was colored stitching and an M logo. I did not really compare them in detail so there may be more differences.
In either case I suspect it will cost a couple grand to buy another wheel and have it installed because of the airbag.
2015 435i Convertible
M Sport, M Performance Power Kit
Last edited by chuck92116; 01-17-2013 at 08:57 PM.