There are 166's made for the 5 series that have 28 mm offsets. There are 166 wheels made for the 6 series with 17 mm offsets.


Both wheels fit either car but will be further out with the 6 series wheel.

The offset is the distance from the interior surface area of the wheel that mounts to the car and the most inner surface of the wheel. Thus a higher offset such as 28 mm will move the wheel closer in to the car where a 17mm offset will push the wheel out more to the fender.

 

+1

 

deifinitely go with spacers for cosmetic... that's y you bought the 166 in the first place.