I wrote an answer to this post a few days ago but it didn't take for some reason.
Its even more appropriate now that some answers are in.
I would recommend a good radiator shop and if necessary a recore. It seems from the answers that a radiator is black and it goes under the hood for a price.
First, the 116 chassis radiator is originally brass and bears no more resemblance to an 81 than to a Ford.
Second, is a radiator a radiator because its black and CHEAP? I must be unusual because when I don't know what I'm doing I always differ to the highest cost item. If you buy a MB radiator for less money, you are wise. If you find out that Behr makes MB radiators and buy it even cheaper you are even wiser. If you find that Nissen makes five different radiators for your car in brass and one of them even meets factory specifications you have found another possibility. BUT if you just go to Radiators are US mailorder and purchase a POS with half the tubes, half the fins and a third the weight for CHEAP don't expect me to fix the problems you have caused. (Me being the rhetorical version of all professional technicians).
If you get a recore the same questions need to be asked. A good radiator shop will know what to do unless you come at them with a cheap attitude. You wouldn't want your MB running around with a customized Yugo radiator would you?
Bosch Master, ASE Master, L1
33 years MB technician