I have taken away some interesting info from a chap who works on the aero on a 488 that competes at LM.
I noted their front splitter was nigh on identical to the one that @Fonzey donated to the cause ( the cause being this idiot
) in terms of the shap.
There were two subtle differences. Either side of the splitter where the curvature is the greatest they have vertical deflectors.
These are there for force the air to stay on the splitter rather than take the path of the least resistance and “fall off” the splitter
You can just about make it out here :

We can also see the rear diffuser is broken into many segments. The idea is not to allow other areas to contaminate each others flows. Hence more sections = better

Some food for thought there
I noted their front splitter was nigh on identical to the one that @Fonzey donated to the cause ( the cause being this idiot

There were two subtle differences. Either side of the splitter where the curvature is the greatest they have vertical deflectors.
These are there for force the air to stay on the splitter rather than take the path of the least resistance and “fall off” the splitter
You can just about make it out here :

We can also see the rear diffuser is broken into many segments. The idea is not to allow other areas to contaminate each others flows. Hence more sections = better

Some food for thought there