And why?
I'm including everything I know of that comes after the word Mustang. Or before. Or instead of, but means that it's a special Mustang
GT
GT500
Cobra
Bullit
R
Parnelli Jones
Rousch
Blackjack
Saleen
Steeda
SDS (San Diego Special)
Foose Stallion
GT350
GT CS (California Special)
Street Scene
Susan G Kolmen pink stripe package
Cannonball World
and if I spent a couple of minutes on the web, I'm sure I could double this list.