They look awesome and are a very nice alternative. Specially to R owners who daily drive their cars and don't want to accidentally damage their Carbon Fibre wheels.
I see it "elsewhere" too. BMW, Mercedes, Lexus, Mitsu (Evos), Subaru (STis), Chrysler (300 SRT8), Dodge (Challenger SRT8)...Just not as common.
It's not our fault that the Mustangs is a TOP 5 brand (Worldwide) in the most beloved, cool looking and popular category.
Anyways, who cares tbh...