I'd like to put smaller wheels on my F56 S.
Are there people out there who could machine to wheel, a little, just so it clears the caliper?

 

I found someone selling 16" wheels.
I pick them up next Monday.
I don't know their name.

 

Yeah, just go with those 16's. I wouldn't try to mod 15's (or other rims) like that. BTW, those are "Loop Spoke" model rims. Sometimes we mention the number of loops on rims, so those would be 5 Loop Spoke rims.

I run OEM 17's summer, and identical 16's with dedicated snows. There is a bit of a difference in handling with the higher side wall on the 16's (and my snows aren't performance rated,) but the trade off is a smoother ride and less chance of damage from winter potholes.
​​​​​Nothing saves me from those pesky summer pot holes,lol. How love New England.

 

I would not modify a wheel for fear of weakening it. Finding those 16 incher that clear was the right thing to do.