[aerohead]

Originally Posted by Phase

https://www.amazon.com/Kyostar-Spoil...3&sr=8-11&th=1

any thoughts on a winglet like this just to use with the curved wheel spats?

I think their target market is the Fast and the Furious crowd. Boy racer stuff. The winglet is apt to create a 'jet' of air, which would be disastrous to the local pressures.
Personally, I'd recommend just blending the rockers into the skirts, and after the skirts, into the sides of the future diffuser. As smooth as possible. Old school.