On my '13 Premium, the ambient lighting controls the color of the doorsills. The window sticker does not list a separate option for lighted sills, it's part of the ambient lighting package.
2013 GT Premium, Red Candy, Brembo, Auto, GT500 Axle-backs.
SOLD! 2008 GT Premium, Vapor Metallic, 5-speed man. w/MGW, Ford Racing M6066 Whipple, GT500 Front end, Spoiler, Suspension and Wheels. GTA's, sequentials, one touch. Can't wipe the smile off my face.