In the bigger ziplock bag, there is another snap on body that requires paint, as well as individual body pieces for the third car, which seems to be some kind of older style coupe or rat rod thing. They all have different difficulty levels, so I couldn't tell you what goes where, but there's 3 sets of wheels and seats, which is what I based the 3 car claim on.
Even if everything's not there, it's more than enough for 2 complete cars and change lol. I think the coupe is the one that would be missing the most, since the other 2 were kept in the same box through most of their short lived model lives.