R owners should have their own forum. I bought my regular old GT350 spontaneously. I didn't know there was such a clique with the R.
Cool shirt BTW. I do like the mugs better though
I'm sure the wheel thieves will thank you for installing the rails, makes their job easier. JK. Actually, I had locking lug nuts for my M2 and never installed them. I figured I never left the car anywhere to warrant needing them. If I had purchased an R, I'm sure I wouldn't be running those...
My guess is the rocker panel splitter is used for aerodynamics and downforce. As the air passes through it should provide force just as the front splitter does. I'm sure there is some cosmetic merit to it as well.
I'm a detail and paint guy and what I've noticed on mine is probably just shoddy work from the factory. I had 2 high end German cars (which were perfect) before this and I've just learned to live with the Ford "flaws".
If you have to have the old ones, here ya go......
https://www.ebay.com/itm/2015-2018-OEM-Ford-Mustang-GT-350-GT350-Inside-Lower-Door-Step-Sill-Plates-Pair/172656558294?hash=item28332200d6:g:bukAAOSw2QJa4eVb