Nice work. Liked the modeling and animation. Did u use a render farm or u rendered on your pc? Also care to share your CPU hardware setup?
If photorealism is what you were going for, a couple of very subtle dirt, dust, and blemishes on the car glasses, metal parts and even scratches,wear and tear on the tyres and wheel covers could have helped. The vehicles look too clean. Also, the transformer robot looks too clean, especially in an environment where speed most likely will develop some dust.
But it is possible a super clean look is what you were going for.