good work...i wish my undertray would extend that far back.
your wheel dams remind me of mine, although i think yours could be bigger,
in observing wheeldams and airdams on production cars, ive noticed a pattern that sugest a fair deal of the dams are aimed at divirting air away from the inner wheel well rather than the tire surface (wich in itself isn't a bad thing)
i initially extended my inner wheel well liners to form a vertical dam that curved inwards
you might want to test this feature on your dam. i got a piece of linoleum on discount to make the dams, but i had so much leftover i stated looking at other applications and basically used it to make dams like you have that would cover most of the initial vertical dams.
i think your dams might be improved upon by making them go straight down at the outside and also much wider on the inside so they cover the inner wheel well more and gently blend with the existing tray.
if you look at your original bumper you notice the outside is a little lower than the inside, so perhaps you could use these dimentions as an indication of where the manifacturer wanted the air to ga and enhance is with a fairing. like this for example
here's what i've made so far although it's still needs improvement
