Was flipping through the documentaries on iTunes. There is a 99 cent rental section that I went in and saw this documentary called "A Faster Horse" which was pretty good. I would give it a 7-8 out of 10.
Anyway, just thought I'd share. I think it's about a year old actually. It focuses on the engineering team making the 2015 mustang
and the other half is about the general history or producing mustangs (it flips back and forth).
The ONLY thing I didn't like is they never focused on details too much but it was pretty cool anyway. One of the first scenes shows how they use a huge clay model (actual dimensions of the car it seems) to sculpt a car design to be able to see it in person.