OK, so completely ignoring anyone's preference on what size of rim looks best I am curious about how rim size might have an impact on performance. I have a 2004 545i with sport suspension. I have no desire to put 20" rims on. I just don't like the look, but I am torn between 18 and 19". Wouldn't the performance of the 18s be better? They should be lighter, easier to get moving, better for braking, etc.

Larger rims are only for looks, correct? In genera, shouldn't smaller be better for performance?

 

not necessarily. it will depend what type of performance you are after as well. typically with a bigger diameter rim, you can have it wider as well and that does make a bit of difference with turning and cornering having a wider stance. there are some light 19s out there too.