I have run several ForTwo's over here over the years and currently have an '03. They do rust in places, the rear wishbones can decay quite nicely, also the rear part of the trideon on each side in the engine bay can start to look pretty scabby after a couple of years. Next time you've got the engine cover off, just take a peek each side, see if it's O.K.
Having said all that, nothing too serious though.