If you've ever wondered what 12mm spacers will do for your F30, here is the answer. Visually it's subtle until you see a car without the spacers next to one that has them.
They couldn't be easier to install, they are fairly light weight, and the stance and handling are noticeably improved. I think spacers are a tremendous bang for the buck mod.
Bought Burger Motorsports spacers used from a forum member.
View from the back, stock.
View from the back, spacers installed.
Stock
Spacers
It works and looks great.