I had an M3 edition with black wheels and they were sooooo hard to keep clean..... They show up everything and you will need to take the wheels off completely every time you wash the car if you want them looking good. The main problem with them is that the rusty colored water from discs ends up on the inside of the rim and you cant get it off unless you wax your wheels and then take them off at each wash.
E46 M3 GTR Race Car
1988 E30 320i track car with 2.7L stroker engine and all the trimmings.
E36 M3 Race Car