My 06 GT Deluxe has leather trimmed door panels. I can't remember if it is standard on all GT's, or if it was because of the IUP?... yes I know, dead horse
Ford added the sport package at a time it couldn't ship the IUP because of a lawsuit over Mycolor. Since that's been resolved the option may no longer exist.
Ok then that would help explain the fact that my 05 was delivered a month earlier than it would have with the Interior Upgrade, plus the demand i suppose.
I have an 06GT Deluxe with a Premium Package. The wording is right from Ford, but maybe the dealer is the reason why we have some many different options. My car came fully loaded with every option even the Shaker 1000, the only thing charged extra was the automatic.