I am making a combination of these two themes for a friend of mine and have come up with a few ideas, but am looking for other ways to incorporate the two themes. I was planning on doing the board like a race track and the bottom tier with road signs and cacti around..not sure how to incorporate Toy Story on the top keeping with that theme..any ideas would be appreciated TIa YAll!

Maybe you could make the entire cake to look like Toy Story scene(s) that had RC (the remote control car), but substitute RC for whichever car(s) you were planning to make from the Cars movie.

I am actually making a two tiered Cars cake at the end of the month. And was thinking of the design I had. It is simialar to yours but I was thinking that you could do one side of the cake to look like CARS and the other to look like TOY STORY! So it will be fun to turn the cake around. Just a thought.

Sounds like a fun cake!

The first image that jumped to mind for me was Woody driving Lightning McQueen?? Not sure if that would work for you, but the image just looks so cute in my head!