The Audi Fox, along with other vehicles of the same era (Ford's German Taunus and American Pinto, GM's German Opel Manta, Toyota's Celica and Carina, Datsun's 610, and BMW's 2002) were considered competitive to the upcoming Fox vehicles and were all considered as having desireable features. The strengths of those vehicles were adapted to and/or improved upon for the Fox vehicles.
The Fox project started out to be a "world car" concept meaning the vehicles were to be small, fuel efficient, sport or family sedans produced throughout Ford's internationl facilities. The concept was supposed to save money by simplifying FoMoCo's international product lineup, offer parts commonality with different models in different countries, and ease planning and production complexity. The world car concept itself never did work out for the Fox vehicles because of, among other things, differences in international safety and other standards and production techniques. The Fox project was obviously continued with the criteria for a world car in mind except it was not produced internationally.
The following vehicles were built on the Fox platform:
'78-'83 Ford Fairmont
'78-'83 Mercury Zephyr
'79-'93 Ford Mustang
'79-'86 Mercury Capri
'80-'82 Ford Granada
'80-'88 Ford Thunderbird
'80-'88 Mercury Cougar
'82-'87 Lincoln Continental
'83-'86 Ford LTD (not to be confused with the Panther chassis-based LTD Crown Victoria)
'83-'86 Mercury Marquis (not to be confused with the Panther chassis-based Grand Marquis)
'84-'92 Lincoln Mark VII | 
