i have the Aero KDM Techinca rubber lip on my YF comes from korea it a different design then the ez-lip it's a 90 degree angle .you can find it on ebay
and i'm working on my own splitter side skirts... still have to round off (Router) the edges
it's pvc trim board it work very well it's sand able, paint able very light and durable, i used it on my Tiburon for splitters in the past.
ad pic for the aero lip
Sonata LIP
Sonata side splitter
PVC front splitter and sides on my old tib