I don't think car companies really knew how big the first Transformers movie could be. They were probably thinking they were just going to use the cars to blow up or just background fodder. They also thought it was just another dumb car movie.
The reason why GM got into it was because of Michael Bay's relationship with them.
So now with Transformers 2, there are so many different car companies involved. When you really think about it, this is the biggest and best opportunity for a car company to get their products plugged without setting up a booth at an Auto Show. They just donate it to the production or present them to the production to see if its suitable for the movie.
Now we got not only American car companies involved but Japanese and European. It is going to one huge action packed car commercial!! Not that its a bad thing. So many people it was a big GM commercial. My thoughts to that........SO WHAT??
Today the latest blog entry states that there is a Smart Car and a Toyota Yaris. So you can really tell the car companies are really trying to get their cars in the movie.
I've seen so many reports of cars in the movie that really stand out but who actually knows if they're just for background. Its possible that the car companies donate the cars to the production. I'm sure the Smart Car and the Toyota Yaris won't actually transform.
Look at how well the movie help sell the actual cars of the Autobots. And so many people painted their Ford Mustang to look like Barricade.
So the car companies definitely know that because this movie is coming out, they're definitely jumping in on the opportunity to market their products.