Is that Prefix splitter the one that looks like the comp coupe 1 piece one instead of the current ACR splitter?
If it is like the 1 piece comp coupe model, I have bonded an aluminum panel to the bottom of them for several race cars and a few street cars. For those that did not want an aluminum "skid plate", I bonded several layers on carbon on the bottom to act as a sacrificial surface.
With regards to rock chips on top, it is one of the things that just happens. There is no precut clear bra, but I imagine that any local clear bra installer worth his salt could custom cut a piece to go on top.