Airdam or Splitter?
 

Just been looking at production cars, and the performance variants seem to have airdams with a horizontal section facing forwards.
Two quick questions - Is that what is known as a splitter, rather than an airdam.
And, as they are designed to provide some downforce (I believe) do they have more drag than a simpler airdam?

Some reading

APR Performance - Splitters

For splitter, a general guideline is 2x longer than the ground clearance to be effective. So if the bumper is 2 inches off the ground, the splitter needs to stick out 4 inches. They are kind of dangerous, and possibly illegal on street cars.

Splitters usually have little effect on drag. In most instances they can reduce lift, but not much on passenger gars, and helps cram more air through the rad.