I think if the rear wings have been replaced then they have a sticky-out bit (technical term lol) as you run your hand round, though that might just be mine.
Check the doors and wings for dings, check the foglights are intact at the front, check the sunroof works (check if it leaks - bucket of water over it perhaps?), tyres, dashboard lights, check the locks all work with the key.
Er... can't think of anything else at the moment! Might be worth taking a note of the previous owner on the logbook so you can try and track him down to ask what the mileage and history of it was when he sold it.