Not a huge issue...
The STi skirts typically are seen on the S206 images. Same is for the STi Sport Muffler. Is it really an S206 exhaust... Yes. Can you find it on others models like the A-line and bases, yes. It's the fact that the part debuts on a particular model and ends up with associated names.
The misconception is the knockoff skirts are labeled directly as S206 side skirts.