Gordon's #24 car will feature a Megatron scheme:

Newman's #39 car will feature Optimus Prime:

(Thanks to Jayski.com for the pics of the cars)
Here's the link to the contest sight where you vote to see who will win the battle between the Autobots (Newman) and Decipticons (Gordon) on the track - a.k.a who finishes ahead of the other.
Click here to see the contest details in full.