I have been. We went to Narnia and we are VERY much looking forward to going to see Cars as well! I cant right this minute put my finger on the promotion information I got in the mail but I think they are having a NASCAR pit crew doing a demonstration before the show? For Narnia it was beautifully decorated (its already a very pretty theatre).
Anyhooo...we sat on the ground floor about three rows from the back and 3 seats in from the left (if you were looking at the screen). They were great seats, but frankly I don't think there are bad seats in the place. The balcony could be fun, but there was a cool effect before the show that we would have missed sitting up there for Narnia. The VIP tickets you order on line include a bottle of soda or water and a popcorn that came in a take-home bucket.
Don't forget to plan to go next door to the Disney Soda Fountain. It is very fun and if you have a group you can get the big sundae that comes on a Sorcerer Mickey Hat and uses an entire can of whipped cream.
There was a line of people to get in, so we got in the line, but you really don't need to. Make sure you get there in plenty of time to see the organist before the show! He is GREAT and plays a wide variety of Disney tunes. We had a ball trying to guess which song it was before the other people in our group.
Also, look for
Disneyland's star (the only "place" to ever get one) that is right in front of the Soda Shops front door as well as the new Winnie the Pooh star. I think Mickey Mouse and Walt Disney have theirs across the street just past the Chinese Theater.
Let me know if you have any other questions.