XRAY - Model racing cars

Looking at some set-ups and looking to understand the Graphite center plate. I get the reason for it's existence and the different screw mounts. What is the purpose for raising or lowering the plate?

Thanks
Darryl

As I understand it the lower the plate the less flex across the chassis, by raising the plate it allows the chassis to flex a little more across it but still stops longitudal flex

From what I've found, less shim (no shim) is more reactive. Adding shims calm it down some. I don't think the initial intent behind shimming the brace up was to adjust feel though, I believe it was just to make the center weight fit under it.