I have heard the VW theroy, but it's hard to imagine. GM and Chrysler always went with Letter Codes for thier bodies, such a A body, B-body, the familiar F-body, and not to mention, the P-body!!! I guess that would be the metro, J/K, there is not P-body. I don't really keep track of them though.
Fox Chassis, but most of us go by Foxbody. Although all mustangs from 79-04 were foxbodies, only the 79-93 are refered to foxbodies. I think as time goes on, even the SN-95's will end up getting the reference of Foxbody because of the base chassis as the 64-78 and the 05+ are so much different. Almost everything is interchangable from 79-04, that is why we have a HUGE aftermarket at a low price. Millions were produced over those years. I think now that the 05 has totally changed DEW platform, it will bring the Foxes and SN's togeather. 79-04 are all brothers, although the younger brothers are kind of fat and heavy, still brothers, but the other mustangs are more cosins.