So as NineFourteener pointed out, the rocker panel decals are a bit of a challenge to install; however, I got NineFourteener's advice before I installed them and it saved me some grief!
The rocker panel decals are a frozen black (a.k.a. Flat, and not Shiny). Note that I added the "M Performance Sticker", and then I had the entire front end of my X5 installed with paint protection film, along with the WHITE section of the rocker panels -- This way, the frozen black rocker panel decals remained flat (instead of shiny due to the PPF) and at the same time the PPF over the white part of the rocker panel also *protected/covered* the M Performance decal making it less likely to be scratched/damaged:
The BMW rocker panel decal appears to make the X5 "vertically slimmer".
