So I thought I'd give a shot at doing some custom Aero Work on my race car project affectionately named Project 22 1NA B.
The rocker areas had rust in them, so I cut them off that seam where the floor pan and side seals, and rocker panel all get spot welded together. I then cleaned them up as best I could, used rust inhibitor very liberally. Once that all sealed, I took a piece of 90d angle aluminum and fitted it to where the rocker panel had attached. I like how it looks aesthetically, but I am not sure how functional it is. Hopefully I will be able to get some track time in and measure lap times as the day goes on by leaving them off and then installing them and then taking them off again.
Once I had it fitted, I notched out the jack points used 5/32" drill bit and about every 3" through the aluminum brace and steel I used kleco pins to hold it in place and then made my template for the side skirt, cut the plastic and molded my rakes, measured out 3-3/4" and drilled out the areas for the nut-certs (M6) once that all matched up, I used 5/32 aluminum rivet to attach the aluminum piece to the car, and then use M6 bolts and appropriate washers to attack the plastic panel to the aluminum brace.
My theory is that it will allow air to escape the front wheel well (reducing the air pressure creating lift in the wheel well) and travel along the tunnel created by the side splitter and area that I opened when cutting out the rocker and folding the good metal in. As it travels down the plane, it will deflect outwards prior to the rear tires, there by reducing the lift effect of air being trapped in the wheel wells.
I really don't know if this will matter though, as my car isn't necessarily fast, it just handles awesome and is quick... but it was fun doing it none-the-less!