This mod is as easy as changing a tire. For those that still may be a bit apprehensive, I took a few pics and made some notes for the install.
I installed 15mm Turner Motorsports spacers on the rear of my 2011 535i (F10). She has the 19" sport wheels with 275/35/19 rubber on the rear.
I am very happy with this mod as I feel that it gives the vehicle a more muscular look. There is no change in ride quality and no vibrations (I had someone sit in the rear and took her up to triple digits to check).
Before starting, make sure to apply the parking brakes! Also remember to recheck the torque on the lugs after 2 weeks of driving. BMW recommends 90 ft-lb of torque.
Materials I used for the install:
anti-seize cream (found only in auto parts store)
Here is the link to the pics and notes for the install:
DIY WHEEL SPACER INSTALL