). A Miata weighs a lot more, and as you said the S2000 is even heavier than a Miata. I use that as a comparison because it's probably the closest thing on the road(except for a Lotus) to the size and weight of an old British sports car.
The MGB was somewhat advanced in having engineered front crumple zones, but it's also easy to see that new cars have a lot more "stuff" in them to keep you safe than the MG.
Just as an example, the last door panel I had off a modern car probably weighed a good 30lbs. Most of the construction is dense foam, and of course the vinyl skin and all the buttons, etc. Behind the panel you usually have additional reinforcement and other "stuff"(including sound deadening) between the panel and the door skin.
I replaced my "door cards" on the MG a month or so back. They're basically a piece of masonite with vinyl covering and a little bit of padding between the two. They came to me in a package that was about 2" thick, and weigh about 10lbs each. When you take them off, you basically only have the window regulator and the door latch/lock mechanism between the card and the skin. The only "extras" you have on the door card are a pull handle and a chrome(or maybe polished aluminum) decorating strip.
If I get hit in that car from the side, I'm basically counting on the door sills to prevent the door from coming too far into the passenger compartment.
BTW, the Miata is about the same length and height as the MG, but I think it's a good 4" or so wider. The passenger compartment itself isn't that much wider-a lot of the width comes from extra stuff to keep you safe in a side impact. My MG mechanic has a wrecked Miata sitting in his shop that he bought from a friend(mostly to rob the seats for an MG). It was a high speed front crash, and the car was about 6" shorter than when it was built. The driver walked away, and if the top had been up they'd have had to pry the door open to get him out.
