Cars was a good pixar movie, but does it really deserve a part 2?
I think the only thing that is left to watch for is the new brands they're going to make an animated version. And of course it's going to come out in 3D. A part 2 I don't think is necessary in my opinion. And of course, people would want to see the coolest real cars in action movies anyway rather than a 3D animation version of it.