[Aerkuld]

Tell him to look at the brake calipers inside the wheel on each car, each caliper is in a different position. Also the Smart car is built around a very strong metal structure which is the silver bit you see from the side. Now look at each car and get him to tell you how they modified that with body panels and managed to completely change the rake of the windscreen. While I'm sure it would be possible to make such nice looking cars it would be an extremely costly and time consuming exercise. To be honest it would probably be easier starting from scratch than modifying an existing Smart car.

If he's still convinced ask him if he's interested in buying a bridge...