Second try at getting an answer

This is not something Gravity Forms is going to do out of the box.

You could use conditional logic to show/hide drop downs based on selections that they make. However, it's going to require you add ALL of the possible drop down combinations to your form and in the case os displaying vehicle information based on model year, make, etc. that is going to be a large number of drop down fields and it's going to be a very cumbersome form to manage. I wouldn't recommend it.

Anything Gravity Forms can't do out of the box it can be made to do via custom code using the available hooks and filters.

The only way to accomplish what you want to do is by implementing your own customization. You would need to write the necessary custom code to create a custom field type that behaves the way you describe. There is a tutorial that discusses how to create a custom field on this 3rd party site here:

http://wpsmith.net/2011/plugins/how-to-create-a-custom-form-field-in-gravity-forms-with-a-terms-of-service-form-field-example/

As for displaying the results in a popup, this would also have to be done as a customization. You would have to apply a customization using jQuery so that the results appear in a new popup window and the form the user was on resets. So you'd attach an event to the form submit to popup the content you want to popup.