Stay with your W202 C220.
If properly maintained, it will be just as reliable as a Toyota Corolla.
You have 400 cc's of extra engine capacity as well.
Yours is in much better condition by the looks of it, than the average W202.
With YOUR particular car, you are not going to have any problems with rust, AND
it is cheaper to run and maintain, compared to a W126 or an R107, with a ragtop, and should present you with fewer problems over the time you are likely to own it.
I have learned to really appreciate my 202, and it is in nowhere as nice as condition as your example. It gets used mainly as runabout.
I have loaned it to three other people so far, all female drivers. They have all learned to greatly appreciate it, despite the fact that, from my experience at least,
women couldn't care less about cars.
All they want is to get where they want to go, with dependability and safety, and without worry.