Thanks guys
Here is a picture that I had.
It is from this site but I couldn't find it in the original post.
Its by Albert 230sl
There is a black part behind the seat which I couldn't figure out what it is.
Flyair, you are right about safety. my car doesn't have the headrests originally and only has lap belts so it is not much different in that aspect. I have some headrests that slides on the back of the seats. I guess they were aftermarket safety pieces for early cars with out headrests. I'll take pictures of them and post them here sometime. The type of rallying that I do is not fast but you have to keep an average speed. so in many parts you may take a corner faster than you might normally do to keep the average speed. sport seats would help in these situations with the side supports.
if I replicate these seats I would probably also built in headrests for them too.
or maybe I should just try to find something like scheel racing seats.
What was in the original red pig I wonder?
it is weird to me that mercedes sold it, then built a replica of it years later.