Thanks for the opinions so far but, aesthetics aside, does anyone think there are negative performance implications to doing something like this (especially considering that my driving style, at best, is "spirited" but rarely anywhere near any real boundaries)?
I mean, when I drove 2 F30 335's back to back, one with 19's and the other with 18's, the one with 19's had a ton more road noise, grind, and tramlined like mad on these sh_tty concrete roads, but at the same time didn't feel all that much more stable or agile (considering my driving style). Same with the older e90 I had.
Based on that experience it seems there's only an aesthetic downside (in some folks opinions)... but these F10's and even the E60 are completely different beasts in terms of ride/handling, so I wonder if 18's would make this car feel squirrely. I did test drive a 535 without the M Sport package on 18's, but I was so distracted by that god-awful standard steering wheel (no offense to those who have it... I just didn't like it at all), I couldn't concentrate on anything else...