I have to say that there is no rust on my wagon apart from a bit, and it is a bit, on the back hinges as thefastone said happens. Also, if you do change the back lights you will have to make sure they fit as they are different.
I love mine though and its not even turbo, but it goes really good & I would recommend it, but I do think you have to have a 'taste' for the wagon! The only problem I find is that occassionally you will find the back end swing, but hey its all part of the fun!
If its a good one, get it and enjoy it!