This information was posted by an insider on another website:

"Inside info, cars are lugging around approximately 500lbs of testing equipment, are all steel (except fascias of coarse) Hoods are some sort of composite, autos AND MANUALS are in the house (manuals are pistol grips), cars apparently move and sound stellar. There are many cars at this testing facility but they are nowhere near production cars yet, the first batch of "show cars" (that will be at Chicago, etc) have not been built yet."