2 quick articles i found from a 30 second google search:
Ford also released a special edition 2000 Mustang GT called the Spring Feature Mustang; all 3,091 units received the same side ducts and hood scoop as the 35th Anniversary Limited Edition GT, as well as black Mustang bumper inserts, dual black stripes on the hood with GT on them, and 17" by 8" bright finish wheels. The 2000 Spring Feature Mustang was the only one offered in Zinc Yellow, a feature that would return to all 2001 Ford Mustangs.
Ford released 3,091 Spring Feature Mustangs for the 2000 model year. The package was offered in Performance Red, Black, Silver, White, and Zinc Yellow, which appeared only on the Spring Feature cars in 2000 and returned in 2001. The package was available only on GTs and included the following features:
Special 17" X 8" bright machined 5-spoke wheels and performance tires
35th Anniversary body-color hood scoop
35th Anniversary body-color side scoops
Twin black stickers on each side of hood scoop with color-keyed GT lettering
Black "MUSTANG" bumper inserts